vue.js

/*!
 * Vue.js v1.0.24
 * (c) 2016 Evan You
 * Released under the MIT License.
 */
(function(global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
        typeof define === 'function' && define.amd ? define(factory) :
        (global.Vue = factory());
}(this, function() {
    'use strict';

    function set(obj, key, val) {
        if (hasOwn(obj, key)) {
            obj[key] = val;
            return;
        }
        if (obj._isVue) {
            set(obj._data, key, val);
            return;
        }
        var ob = obj.__ob__;
        if (!ob) {
            obj[key] = val;
            return;
        }
        ob.convert(key, val);
        ob.dep.notify();
        if (ob.vms) {
            var i = ob.vms.length;
            while (i--) {
                var vm = ob.vms[i];
                vm._proxy(key);
                vm._digest();
            }
        }
        return val;
    }

    /**
     * Delete a property and trigger change if necessary.
     *
     * @param {Object} obj
     * @param {String} key
     */

    function del(obj, key) {
        if (!hasOwn(obj, key)) {
            return;
        }
        delete obj[key];
        var ob = obj.__ob__;
        if (!ob) {
            if (obj._isVue) {
                delete obj._data[key];
                obj._digest();
            }
            return;
        }
        ob.dep.notify();
        if (ob.vms) {
            var i = ob.vms.length;
            while (i--) {
                var vm = ob.vms[i];
                vm._unproxy(key);
                vm._digest();
            }
        }
    }

    var hasOwnProperty = Object.prototype.hasOwnProperty;
    /**
     * Check whether the object has the property.
     *
     * @param {Object} obj
     * @param {String} key
     * @return {Boolean}
     */

    function hasOwn(obj, key) {
        return hasOwnProperty.call(obj, key);
    }

    /**
     * Check if an expression is a literal value.
     *
     * @param {String} exp
     * @return {Boolean}
     */

    var literalValueRE = /^\s?(true|false|-?[\d\.]+|'[^']*'|"[^"]*")\s?$/;

    function isLiteral(exp) {
        return literalValueRE.test(exp);
    }

    /**
     * Check if a string starts with $ or _
     *
     * @param {String} str
     * @return {Boolean}
     */

    function isReserved(str) {
        var c = (str + '').charCodeAt(0);
        return c === 0x24 || c === 0x5F;
    }

    /**
     * Guard text output, make sure undefined outputs
     * empty string
     *
     * @param {*} value
     * @return {String}
     */

    function _toString(value) {
        return value == null ? '' : value.toString();
    }

    /**
     * Check and convert possible numeric strings to numbers
     * before setting back to data
     *
     * @param {*} value
     * @return {*|Number}
     */

    function toNumber(value) {
        if (typeof value !== 'string') {
            return value;
        } else {
            var parsed = Number(value);
            return isNaN(parsed) ? value : parsed;
        }
    }

    /**
     * Convert string boolean literals into real booleans.
     *
     * @param {*} value
     * @return {*|Boolean}
     */

    function toBoolean(value) {
        return value === 'true' ? true : value === 'false' ? false : value;
    }

    /**
     * Strip quotes from a string
     *
     * @param {String} str
     * @return {String | false}
     */

    function stripQuotes(str) {
        var a = str.charCodeAt(0);
        var b = str.charCodeAt(str.length - 1);
        return a === b && (a === 0x22 || a === 0x27) ? str.slice(1, -1) : str;
    }

    /**
     * Camelize a hyphen-delmited string.
     *
     * @param {String} str
     * @return {String}
     */

    var camelizeRE = /-(\w)/g;

    function camelize(str) {
        return str.replace(camelizeRE, toUpper);
    }

    function toUpper(_, c) {
        return c ? c.toUpperCase() : '';
    }

    /**
     * Hyphenate a camelCase string.
     *
     * @param {String} str
     * @return {String}
     */

    var hyphenateRE = /([a-z\d])([A-Z])/g;

    function hyphenate(str) {
        return str.replace(hyphenateRE, '$1-$2').toLowerCase();
    }

    /**
     * Converts hyphen/underscore/slash delimitered names into
     * camelized classNames.
     *
     * e.g. my-component => MyComponent
     *      some_else    => SomeElse
     *      some/comp    => SomeComp
     *
     * @param {String} str
     * @return {String}
     */

    var classifyRE = /(?:^|[-_\/])(\w)/g;

    function classify(str) {
        return str.replace(classifyRE, toUpper);
    }

    /**
     * Simple bind, faster than native
     *
     * @param {Function} fn
     * @param {Object} ctx
     * @return {Function}
     */

    function bind(fn, ctx) {
        return function(a) {
            var l = arguments.length;
            return l ? l > 1 ? fn.apply(ctx, arguments) : fn.call(ctx, a) : fn.call(ctx);
        };
    }

    /**
     * Convert an Array-like object to a real Array.
     *
     * @param {Array-like} list
     * @param {Number} [start] - start index
     * @return {Array}
     */

    function toArray(list, start) {
        start = start || 0;
        var i = list.length - start;
        var ret = new Array(i);
        while (i--) {
            ret[i] = list[i + start];
        }
        return ret;
    }

    /**
     * Mix properties into target object.
     *
     * @param {Object} to
     * @param {Object} from
     */

    function extend(to, from) {
        var keys = Object.keys(from);
        var i = keys.length;
        while (i--) {
            to[keys[i]] = from[keys[i]];
        }
        return to;
    }

    /**
     * Quick object check - this is primarily used to tell
     * Objects from primitive values when we know the value
     * is a JSON-compliant type.
     *
     * @param {*} obj
     * @return {Boolean}
     */

    function isObject(obj) {
        return obj !== null && typeof obj === 'object';
    }

    /**
     * Strict object type check. Only returns true
     * for plain JavaScript objects.
     *
     * @param {*} obj
     * @return {Boolean}
     */

    var toString = Object.prototype.toString;
    var OBJECT_STRING = '[object Object]';

    function isPlainObject(obj) {
        return toString.call(obj) === OBJECT_STRING;
    }

    /**
     * Array type check.
     *
     * @param {*} obj
     * @return {Boolean}
     */

    var isArray = Array.isArray;

    /**
     * Define a property.
     *
     * @param {Object} obj
     * @param {String} key
     * @param {*} val
     * @param {Boolean} [enumerable]
     */

    function def(obj, key, val, enumerable) {
        Object.defineProperty(obj, key, {
            value: val,
            enumerable: !!enumerable,
            writable: true,
            configurable: true
        });
    }

    /**
     * Debounce a function so it only gets called after the
     * input stops arriving after the given wait period.
     *
     * @param {Function} func
     * @param {Number} wait
     * @return {Function} - the debounced function
     */

    function _debounce(func, wait) {
        var timeout, args, context, timestamp, result;
        var later = function later() {
            var last = Date.now() - timestamp;
            if (last < wait && last >= 0) {
                timeout = setTimeout(later, wait - last);
            } else {
                timeout = null;
                result = func.apply(context, args);
                if (!timeout) context = args = null;
            }
        };
        return function() {
            context = this;
            args = arguments;
            timestamp = Date.now();
            if (!timeout) {
                timeout = setTimeout(later, wait);
            }
            return result;
        };
    }

    /**
     * Manual indexOf because it's slightly faster than
     * native.
     *
     * @param {Array} arr
     * @param {*} obj
     */

    function indexOf(arr, obj) {
        var i = arr.length;
        while (i--) {
            if (arr[i] === obj) return i;
        }
        return -1;
    }

    /**
     * Make a cancellable version of an async callback.
     *
     * @param {Function} fn
     * @return {Function}
     */

    function cancellable(fn) {
        var cb = function cb() {
            if (!cb.cancelled) {
                return fn.apply(this, arguments);
            }
        };
        cb.cancel = function() {
            cb.cancelled = true;
        };
        return cb;
    }

    /**
     * Check if two values are loosely equal - that is,
     * if they are plain objects, do they have the same shape?
     *
     * @param {*} a
     * @param {*} b
     * @return {Boolean}
     */

    function looseEqual(a, b) {
        /* eslint-disable eqeqeq */
        return a == b || (isObject(a) && isObject(b) ? JSON.stringify(a) === JSON.stringify(b) : false);
        /* eslint-enable eqeqeq */
    }

    var hasProto = ('__proto__' in {});

    // Browser environment sniffing
    var inBrowser = typeof window !== 'undefined' && Object.prototype.toString.call(window) !== '[object Object]';

    // detect devtools
    var devtools = inBrowser && window.__VUE_DEVTOOLS_GLOBAL_HOOK__;

    // UA sniffing for working around browser-specific quirks
    var UA = inBrowser && window.navigator.userAgent.toLowerCase();
    var isIE9 = UA && UA.indexOf('msie 9.0') > 0;
    var isAndroid = UA && UA.indexOf('android') > 0;
    var isIos = UA && /(iphone|ipad|ipod|ios)/i.test(UA);
    var isWechat = UA && UA.indexOf('micromessenger') > 0;

    var transitionProp = undefined;
    var transitionEndEvent = undefined;
    var animationProp = undefined;
    var animationEndEvent = undefined;

    // Transition property/event sniffing
    if (inBrowser && !isIE9) {
        var isWebkitTrans = window.ontransitionend === undefined && window.onwebkittransitionend !== undefined;
        var isWebkitAnim = window.onanimationend === undefined && window.onwebkitanimationend !== undefined;
        transitionProp = isWebkitTrans ? 'WebkitTransition' : 'transition';
        transitionEndEvent = isWebkitTrans ? 'webkitTransitionEnd' : 'transitionend';
        animationProp = isWebkitAnim ? 'WebkitAnimation' : 'animation';
        animationEndEvent = isWebkitAnim ? 'webkitAnimationEnd' : 'animationend';
    }

    /**
     * Defer a task to execute it asynchronously. Ideally this
     * should be executed as a microtask, so we leverage
     * MutationObserver if it's available, and fallback to
     * setTimeout(0).
     *
     * @param {Function} cb
     * @param {Object} ctx
     */

    var nextTick = (function() {
        var callbacks = [];
        var pending = false;
        var timerFunc;

        function nextTickHandler() {
            pending = false;
            var copies = callbacks.slice(0);
            callbacks = [];
            for (var i = 0; i < copies.length; i++) {
                copies[i]();
            }
        }

        /* istanbul ignore if */
        if (typeof MutationObserver !== 'undefined' && !(isWechat && isIos)) {
            var counter = 1;
            var observer = new MutationObserver(nextTickHandler);
            var textNode = document.createTextNode(counter);
            observer.observe(textNode, {
                characterData: true
            });
            timerFunc = function() {
                counter = (counter + 1) % 2;
                textNode.data = counter;
            };
        } else {
            // webpack attempts to inject a shim for setImmediate
            // if it is used as a global, so we have to work around that to
            // avoid bundling unnecessary code.
            var context = inBrowser ? window : typeof global !== 'undefined' ? global : {};
            timerFunc = context.setImmediate || setTimeout;
        }
        return function(cb, ctx) {
            var func = ctx ? function() {
                cb.call(ctx);
            } : cb;
            callbacks.push(func);
            if (pending) return;
            pending = true;
            timerFunc(nextTickHandler, 0);
        };
    })();

    var _Set = undefined;
    /* istanbul ignore if */
    if (typeof Set !== 'undefined' && Set.toString().match(/native code/)) {
        // use native Set when available.
        _Set = Set;
    } else {
        // a non-standard Set polyfill that only works with primitive keys.
        _Set = function() {
            this.set = Object.create(null);
        };
        _Set.prototype.has = function(key) {
            return this.set[key] !== undefined;
        };
        _Set.prototype.add = function(key) {
            this.set[key] = 1;
        };
        _Set.prototype.clear = function() {
            this.set = Object.create(null);
        };
    }

    function Cache(limit) {
        this.size = 0;
        this.limit = limit;
        this.head = this.tail = undefined;
        this._keymap = Object.create(null);
    }

    var p = Cache.prototype;

    /**
     * Put <value> into the cache associated with <key>.
     * Returns the entry which was removed to make room for
     * the new entry. Otherwise undefined is returned.
     * (i.e. if there was enough room already).
     *
     * @param {String} key
     * @param {*} value
     * @return {Entry|undefined}
     */

    p.put = function(key, value) {
        var removed;
        if (this.size === this.limit) {
            removed = this.shift();
        }

        var entry = this.get(key, true);
        if (!entry) {
            entry = {
                key: key
            };
            this._keymap[key] = entry;
            if (this.tail) {
                this.tail.newer = entry;
                entry.older = this.tail;
            } else {
                this.head = entry;
            }
            this.tail = entry;
            this.size++;
        }
        entry.value = value;

        return removed;
    };

    /**
     * Purge the least recently used (oldest) entry from the
     * cache. Returns the removed entry or undefined if the
     * cache was empty.
     */

    p.shift = function() {
        var entry = this.head;
        if (entry) {
            this.head = this.head.newer;
            this.head.older = undefined;
            entry.newer = entry.older = undefined;
            this._keymap[entry.key] = undefined;
            this.size--;
        }
        return entry;
    };

    /**
     * Get and register recent use of <key>. Returns the value
     * associated with <key> or undefined if not in cache.
     *
     * @param {String} key
     * @param {Boolean} returnEntry
     * @return {Entry|*}
     */

    p.get = function(key, returnEntry) {
        var entry = this._keymap[key];
        if (entry === undefined) return;
        if (entry === this.tail) {
            return returnEntry ? entry : entry.value;
        }
        // HEAD--------------TAIL
        //   <.older   .newer>
        //  <--- add direction --
        //   A  B  C  <D>  E
        if (entry.newer) {
            if (entry === this.head) {
                this.head = entry.newer;
            }
            entry.newer.older = entry.older; // C <-- E.
        }
        if (entry.older) {
            entry.older.newer = entry.newer; // C. --> E
        }
        entry.newer = undefined; // D --x
        entry.older = this.tail; // D. --> E
        if (this.tail) {
            this.tail.newer = entry; // E. <-- D
        }
        this.tail = entry;
        return returnEntry ? entry : entry.value;
    };

    var cache$1 = new Cache(1000);
    var filterTokenRE = /[^\s'"]+|'[^']*'|"[^"]*"/g;
    var reservedArgRE = /^in$|^-?\d+/;

    /**
     * Parser state
     */

    var str;
    var dir;
    var c;
    var prev;
    var i;
    var l;
    var lastFilterIndex;
    var inSingle;
    var inDouble;
    var curly;
    var square;
    var paren;
    /**
     * Push a filter to the current directive object
     */

    function pushFilter() {
        var exp = str.slice(lastFilterIndex, i).trim();
        var filter;
        if (exp) {
            filter = {};
            var tokens = exp.match(filterTokenRE);
            filter.name = tokens[0];
            if (tokens.length > 1) {
                filter.args = tokens.slice(1).map(processFilterArg);
            }
        }
        if (filter) {
            (dir.filters = dir.filters || []).push(filter);
        }
        lastFilterIndex = i + 1;
    }

    /**
     * Check if an argument is dynamic and strip quotes.
     *
     * @param {String} arg
     * @return {Object}
     */

    function processFilterArg(arg) {
        if (reservedArgRE.test(arg)) {
            return {
                value: toNumber(arg),
                dynamic: false
            };
        } else {
            var stripped = stripQuotes(arg);
            var dynamic = stripped === arg;
            return {
                value: dynamic ? arg : stripped,
                dynamic: dynamic
            };
        }
    }

    /**
     * Parse a directive value and extract the expression
     * and its filters into a descriptor.
     *
     * Example:
     *
     * "a + 1 | uppercase" will yield:
     * {
     *   expression: 'a + 1',
     *   filters: [
     *     { name: 'uppercase', args: null }
     *   ]
     * }
     *
     * @param {String} s
     * @return {Object}
     */

    function parseDirective(s) {
        var hit = cache$1.get(s);
        if (hit) {
            return hit;
        }

        // reset parser state
        str = s;
        inSingle = inDouble = false;
        curly = square = paren = 0;
        lastFilterIndex = 0;
        dir = {};

        for (i = 0, l = str.length; i < l; i++) {
            prev = c;
            c = str.charCodeAt(i);
            if (inSingle) {
                // check single quote
                if (c === 0x27 && prev !== 0x5C) inSingle = !inSingle;
            } else if (inDouble) {
                // check double quote
                if (c === 0x22 && prev !== 0x5C) inDouble = !inDouble;
            } else if (c === 0x7C && // pipe
                str.charCodeAt(i + 1) !== 0x7C && str.charCodeAt(i - 1) !== 0x7C) {
                if (dir.expression == null) {
                    // first filter, end of expression
                    lastFilterIndex = i + 1;
                    dir.expression = str.slice(0, i).trim();
                } else {
                    // already has filter
                    pushFilter();
                }
            } else {
                switch (c) {
                    case 0x22:
                        inDouble = true;
                        break; // "
                    case 0x27:
                        inSingle = true;
                        break; // '
                    case 0x28:
                        paren++;
                        break; // (
                    case 0x29:
                        paren--;
                        break; // )
                    case 0x5B:
                        square++;
                        break; // [
                    case 0x5D:
                        square--;
                        break; // ]
                    case 0x7B:
                        curly++;
                        break; // {
                    case 0x7D:
                        curly--;
                        break; // }
                }
            }
        }

        if (dir.expression == null) {
            dir.expression = str.slice(0, i).trim();
        } else if (lastFilterIndex !== 0) {
            pushFilter();
        }

        cache$1.put(s, dir);
        return dir;
    }

    var directive = Object.freeze({
        parseDirective: parseDirective
    });

    var regexEscapeRE = /[-.*+?^${}()|[\]\/\\]/g;
    var cache = undefined;
    var tagRE = undefined;
    var htmlRE = undefined;
    /**
     * Escape a string so it can be used in a RegExp
     * constructor.
     *
     * @param {String} str
     */

    function escapeRegex(str) {
        return str.replace(regexEscapeRE, '\\$&');
    }

    function compileRegex() {
        var open = escapeRegex(config.delimiters[0]);
        var close = escapeRegex(config.delimiters[1]);
        var unsafeOpen = escapeRegex(config.unsafeDelimiters[0]);
        var unsafeClose = escapeRegex(config.unsafeDelimiters[1]);
        tagRE = new RegExp(unsafeOpen + '((?:.|\\n)+?)' + unsafeClose + '|' + open + '((?:.|\\n)+?)' + close, 'g');
        htmlRE = new RegExp('^' + unsafeOpen + '.*' + unsafeClose + '$');
        // reset cache
        cache = new Cache(1000);
    }

    /**
     * Parse a template text string into an array of tokens.
     *
     * @param {String} text
     * @return {Array<Object> | null}
     *               - {String} type
     *               - {String} value
     *               - {Boolean} [html]
     *               - {Boolean} [oneTime]
     */

    function parseText(text) {
        if (!cache) {
            compileRegex();
        }
        var hit = cache.get(text);
        if (hit) {
            return hit;
        }
        if (!tagRE.test(text)) {
            return null;
        }
        var tokens = [];
        var lastIndex = tagRE.lastIndex = 0;
        var match, index, html, value, first, oneTime;
        /* eslint-disable no-cond-assign */
        while (match = tagRE.exec(text)) {
            /* eslint-enable no-cond-assign */
            index = match.index;
            // push text token
            if (index > lastIndex) {
                tokens.push({
                    value: text.slice(lastIndex, index)
                });
            }
            // tag token
            html = htmlRE.test(match[0]);
            value = html ? match[1] : match[2];
            first = value.charCodeAt(0);
            oneTime = first === 42; // *
            value = oneTime ? value.slice(1) : value;
            tokens.push({
                tag: true,
                value: value.trim(),
                html: html,
                oneTime: oneTime
            });
            lastIndex = index + match[0].length;
        }
        if (lastIndex < text.length) {
            tokens.push({
                value: text.slice(lastIndex)
            });
        }
        cache.put(text, tokens);
        return tokens;
    }

    /**
     * Format a list of tokens into an expression.
     * e.g. tokens parsed from 'a {{b}} c' can be serialized
     * into one single expression as '"a " + b + " c"'.
     *
     * @param {Array} tokens
     * @param {Vue} [vm]
     * @return {String}
     */

    function tokensToExp(tokens, vm) {
        if (tokens.length > 1) {
            return tokens.map(function(token) {
                return formatToken(token, vm);
            }).join('+');
        } else {
            return formatToken(tokens[0], vm, true);
        }
    }

    /**
     * Format a single token.
     *
     * @param {Object} token
     * @param {Vue} [vm]
     * @param {Boolean} [single]
     * @return {String}
     */

    function formatToken(token, vm, single) {
        return token.tag ? token.oneTime && vm ? '"' + vm.$eval(token.value) + '"' : inlineFilters(token.value, single) : '"' + token.value + '"';
    }

    /**
     * For an attribute with multiple interpolation tags,
     * e.g. attr="some-{{thing | filter}}", in order to combine
     * the whole thing into a single watchable expression, we
     * have to inline those filters. This function does exactly
     * that. This is a bit hacky but it avoids heavy changes
     * to directive parser and watcher mechanism.
     *
     * @param {String} exp
     * @param {Boolean} single
     * @return {String}
     */

    var filterRE = /[^|]\|[^|]/;

    function inlineFilters(exp, single) {
        if (!filterRE.test(exp)) {
            return single ? exp : '(' + exp + ')';
        } else {
            var dir = parseDirective(exp);
            if (!dir.filters) {
                return '(' + exp + ')';
            } else {
                return 'this._applyFilters(' + dir.expression + // value
                    ',null,' + // oldValue (null for read)
                    JSON.stringify(dir.filters) + // filter descriptors
                    ',false)'; // write?
            }
        }
    }

    var text = Object.freeze({
        compileRegex: compileRegex,
        parseText: parseText,
        tokensToExp: tokensToExp
    });

    var delimiters = ['{{', '}}'];
    var unsafeDelimiters = ['{{{', '}}}'];

    var config = Object.defineProperties({

        /**
         * Whether to print debug messages.
         * Also enables stack trace for warnings.
         *
         * @type {Boolean}
         */

        debug: false,

        /**
         * Whether to suppress warnings.
         *
         * @type {Boolean}
         */

        silent: false,

        /**
         * Whether to use async rendering.
         */

        async: true,

        /**
         * Whether to warn against errors caught when evaluating
         * expressions.
         */

        warnExpressionErrors: true,

        /**
         * Whether to allow devtools inspection.
         * Disabled by default in production builds.
         */

        devtools: 'development' !== 'production',

        /**
         * Internal flag to indicate the delimiters have been
         * changed.
         *
         * @type {Boolean}
         */

        _delimitersChanged: true,

        /**
         * List of asset types that a component can own.
         *
         * @type {Array}
         */

        _assetTypes: ['component', 'directive', 'elementDirective', 'filter', 'transition', 'partial'],

        /**
         * prop binding modes
         */

        _propBindingModes: {
            ONE_WAY: 0,
            TWO_WAY: 1,
            ONE_TIME: 2
        },

        /**
         * Max circular updates allowed in a batcher flush cycle.
         */

        _maxUpdateCount: 100

    }, {
        delimiters: {
            /**
             * Interpolation delimiters. Changing these would trigger
             * the text parser to re-compile the regular expressions.
             *
             * @type {Array<String>}
             */

            get: function get() {
                return delimiters;
            },
            set: function set(val) {
                delimiters = val;
                compileRegex();
            },
            configurable: true,
            enumerable: true
        },
        unsafeDelimiters: {
            get: function get() {
                return unsafeDelimiters;
            },
            set: function set(val) {
                unsafeDelimiters = val;
                compileRegex();
            },
            configurable: true,
            enumerable: true
        }
    });

    var warn = undefined;
    var formatComponentName = undefined;

    if ('development' !== 'production') {
        (function() {
            var hasConsole = typeof console !== 'undefined';

            warn = function(msg, vm) {
                if (hasConsole && !config.silent) {
                    console.error('[Vue warn]: ' + msg + (vm ? formatComponentName(vm) : ''));
                }
            };

            formatComponentName = function(vm) {
                var name = vm._isVue ? vm.$options.name : vm.name;
                return name ? ' (found in component: <' + hyphenate(name) + '>)' : '';
            };
        })();
    }

    /**
     * Append with transition.
     *
     * @param {Element} el
     * @param {Element} target
     * @param {Vue} vm
     * @param {Function} [cb]
     */

    function appendWithTransition(el, target, vm, cb) {
        applyTransition(el, 1, function() {
            target.appendChild(el);
        }, vm, cb);
    }

    /**
     * InsertBefore with transition.
     *
     * @param {Element} el
     * @param {Element} target
     * @param {Vue} vm
     * @param {Function} [cb]
     */

    function beforeWithTransition(el, target, vm, cb) {
        applyTransition(el, 1, function() {
            before(el, target);
        }, vm, cb);
    }

    /**
     * Remove with transition.
     *
     * @param {Element} el
     * @param {Vue} vm
     * @param {Function} [cb]
     */

    function removeWithTransition(el, vm, cb) {
        applyTransition(el, -1, function() {
            remove(el);
        }, vm, cb);
    }

    /**
     * Apply transitions with an operation callback.
     *
     * @param {Element} el
     * @param {Number} direction
     *                  1: enter
     *                 -1: leave
     * @param {Function} op - the actual DOM operation
     * @param {Vue} vm
     * @param {Function} [cb]
     */

    function applyTransition(el, direction, op, vm, cb) {
        var transition = el.__v_trans;
        if (!transition ||
            // skip if there are no js hooks and CSS transition is
            // not supported
            !transition.hooks && !transitionEndEvent ||
            // skip transitions for initial compile
            !vm._isCompiled ||
            // if the vm is being manipulated by a parent directive
            // during the parent's compilation phase, skip the
            // animation.
            vm.$parent && !vm.$parent._isCompiled) {
            op();
            if (cb) cb();
            return;
        }
        var action = direction > 0 ? 'enter' : 'leave';
        transition[action](op, cb);
    }

    var transition = Object.freeze({
        appendWithTransition: appendWithTransition,
        beforeWithTransition: beforeWithTransition,
        removeWithTransition: removeWithTransition,
        applyTransition: applyTransition
    });

    /**
     * Query an element selector if it's not an element already.
     *
     * @param {String|Element} el
     * @return {Element}
     */

    function query(el) {
        if (typeof el === 'string') {
            var selector = el;
            el = document.querySelector(el);
            if (!el) {
                'development' !== 'production' && warn('Cannot find element: ' + selector);
            }
        }
        return el;
    }

    /**
     * Check if a node is in the document.
     * Note: document.documentElement.contains should work here
     * but always returns false for comment nodes in phantomjs,
     * making unit tests difficult. This is fixed by doing the
     * contains() check on the node's parentNode instead of
     * the node itself.
     *
     * @param {Node} node
     * @return {Boolean}
     */

    function inDoc(node) {
        if (!node) return false;
        var doc = node.ownerDocument.documentElement;
        var parent = node.parentNode;
        return doc === node || doc === parent || !!(parent && parent.nodeType === 1 && doc.contains(parent));
    }

    /**
     * Get and remove an attribute from a node.
     *
     * @param {Node} node
     * @param {String} _attr
     */

    function getAttr(node, _attr) {
        var val = node.getAttribute(_attr);
        if (val !== null) {
            node.removeAttribute(_attr);
        }
        return val;
    }

    /**
     * Get an attribute with colon or v-bind: prefix.
     *
     * @param {Node} node
     * @param {String} name
     * @return {String|null}
     */

    function getBindAttr(node, name) {
        var val = getAttr(node, ':' + name);
        if (val === null) {
            val = getAttr(node, 'v-bind:' + name);
        }
        return val;
    }

    /**
     * Check the presence of a bind attribute.
     *
     * @param {Node} node
     * @param {String} name
     * @return {Boolean}
     */

    function hasBindAttr(node, name) {
        return node.hasAttribute(name) || node.hasAttribute(':' + name) || node.hasAttribute('v-bind:' + name);
    }

    /**
     * Insert el before target
     *
     * @param {Element} el
     * @param {Element} target
     */

    function before(el, target) {
        target.parentNode.insertBefore(el, target);
    }

    /**
     * Insert el after target
     *
     * @param {Element} el
     * @param {Element} target
     */

    function after(el, target) {
        if (target.nextSibling) {
            before(el, target.nextSibling);
        } else {
            target.parentNode.appendChild(el);
        }
    }

    /**
     * Remove el from DOM
     *
     * @param {Element} el
     */

    function remove(el) {
        el.parentNode.removeChild(el);
    }

    /**
     * Prepend el to target
     *
     * @param {Element} el
     * @param {Element} target
     */

    function prepend(el, target) {
        if (target.firstChild) {
            before(el, target.firstChild);
        } else {
            target.appendChild(el);
        }
    }

    /**
     * Replace target with el
     *
     * @param {Element} target
     * @param {Element} el
     */

    function replace(target, el) {
        var parent = target.parentNode;
        if (parent) {
            parent.replaceChild(el, target);
        }
    }

    /**
     * Add event listener shorthand.
     *
     * @param {Element} el
     * @param {String} event
     * @param {Function} cb
     * @param {Boolean} [useCapture]
     */

    function on(el, event, cb, useCapture) {
        el.addEventListener(event, cb, useCapture);
    }

    /**
     * Remove event listener shorthand.
     *
     * @param {Element} el
     * @param {String} event
     * @param {Function} cb
     */

    function off(el, event, cb) {
        el.removeEventListener(event, cb);
    }

    /**
     * For IE9 compat: when both class and :class are present
     * getAttribute('class') returns wrong value...
     *
     * @param {Element} el
     * @return {String}
     */

    function getClass(el) {
        var classname = el.className;
        if (typeof classname === 'object') {
            classname = classname.baseVal || '';
        }
        return classname;
    }

    /**
     * In IE9, setAttribute('class') will result in empty class
     * if the element also has the :class attribute; However in
     * PhantomJS, setting `className` does not work on SVG elements...
     * So we have to do a conditional check here.
     *
     * @param {Element} el
     * @param {String} cls
     */

    function setClass(el, cls) {
        /* istanbul ignore if */
        if (isIE9 && !/svg$/.test(el.namespaceURI)) {
            el.className = cls;
        } else {
            el.setAttribute('class', cls);
        }
    }

    /**
     * Add class with compatibility for IE & SVG
     *
     * @param {Element} el
     * @param {String} cls
     */

    function addClass(el, cls) {
        if (el.classList) {
            el.classList.add(cls);
        } else {
            var cur = ' ' + getClass(el) + ' ';
            if (cur.indexOf(' ' + cls + ' ') < 0) {
                setClass(el, (cur + cls).trim());
            }
        }
    }

    /**
     * Remove class with compatibility for IE & SVG
     *
     * @param {Element} el
     * @param {String} cls
     */

    function removeClass(el, cls) {
        if (el.classList) {
            el.classList.remove(cls);
        } else {
            var cur = ' ' + getClass(el) + ' ';
            var tar = ' ' + cls + ' ';
            while (cur.indexOf(tar) >= 0) {
                cur = cur.replace(tar, ' ');
            }
            setClass(el, cur.trim());
        }
        if (!el.className) {
            el.removeAttribute('class');
        }
    }

    /**
     * Extract raw content inside an element into a temporary
     * container div
     *
     * @param {Element} el
     * @param {Boolean} asFragment
     * @return {Element|DocumentFragment}
     */

    function extractContent(el, asFragment) {
        var child;
        var rawContent;
        /* istanbul ignore if */
        if (isTemplate(el) && isFragment(el.content)) {
            el = el.content;
        }
        if (el.hasChildNodes()) {
            trimNode(el);
            rawContent = asFragment ? document.createDocumentFragment() : document.createElement('div');
            /* eslint-disable no-cond-assign */
            while (child = el.firstChild) {
                /* eslint-enable no-cond-assign */
                rawContent.appendChild(child);
            }
        }
        return rawContent;
    }

    /**
     * Trim possible empty head/tail text and comment
     * nodes inside a parent.
     *
     * @param {Node} node
     */

    function trimNode(node) {
        var child;
        /* eslint-disable no-sequences */
        while ((child = node.firstChild, isTrimmable(child))) {
            node.removeChild(child);
        }
        while ((child = node.lastChild, isTrimmable(child))) {
            node.removeChild(child);
        }
        /* eslint-enable no-sequences */
    }

    function isTrimmable(node) {
        return node && (node.nodeType === 3 && !node.data.trim() || node.nodeType === 8);
    }

    /**
     * Check if an element is a template tag.
     * Note if the template appears inside an SVG its tagName
     * will be in lowercase.
     *
     * @param {Element} el
     */

    function isTemplate(el) {
        return el.tagName && el.tagName.toLowerCase() === 'template';
    }

    /**
     * Create an "anchor" for performing dom insertion/removals.
     * This is used in a number of scenarios:
     * - fragment instance
     * - v-html
     * - v-if
     * - v-for
     * - component
     *
     * @param {String} content
     * @param {Boolean} persist - IE trashes empty textNodes on
     *                            cloneNode(true), so in certain
     *                            cases the anchor needs to be
     *                            non-empty to be persisted in
     *                            templates.
     * @return {Comment|Text}
     */

    function createAnchor(content, persist) {
        var anchor = config.debug ? document.createComment(content) : document.createTextNode(persist ? ' ' : '');
        anchor.__v_anchor = true;
        return anchor;
    }

    /**
     * Find a component ref attribute that starts with $.
     *
     * @param {Element} node
     * @return {String|undefined}
     */

    var refRE = /^v-ref:/;

    function findRef(node) {
        if (node.hasAttributes()) {
            var attrs = node.attributes;
            for (var i = 0, l = attrs.length; i < l; i++) {
                var name = attrs[i].name;
                if (refRE.test(name)) {
                    return camelize(name.replace(refRE, ''));
                }
            }
        }
    }

    /**
     * Map a function to a range of nodes .
     *
     * @param {Node} node
     * @param {Node} end
     * @param {Function} op
     */

    function mapNodeRange(node, end, op) {
        var next;
        while (node !== end) {
            next = node.nextSibling;
            op(node);
            node = next;
        }
        op(end);
    }

    /**
     * Remove a range of nodes with transition, store
     * the nodes in a fragment with correct ordering,
     * and call callback when done.
     *
     * @param {Node} start
     * @param {Node} end
     * @param {Vue} vm
     * @param {DocumentFragment} frag
     * @param {Function} cb
     */

    function removeNodeRange(start, end, vm, frag, cb) {
        var done = false;
        var removed = 0;
        var nodes = [];
        mapNodeRange(start, end, function(node) {
            if (node === end) done = true;
            nodes.push(node);
            removeWithTransition(node, vm, onRemoved);
        });

        function onRemoved() {
            removed++;
            if (done && removed >= nodes.length) {
                for (var i = 0; i < nodes.length; i++) {
                    frag.appendChild(nodes[i]);
                }
                cb && cb();
            }
        }
    }

    /**
     * Check if a node is a DocumentFragment.
     *
     * @param {Node} node
     * @return {Boolean}
     */

    function isFragment(node) {
        return node && node.nodeType === 11;
    }

    /**
     * Get outerHTML of elements, taking care
     * of SVG elements in IE as well.
     *
     * @param {Element} el
     * @return {String}
     */

    function getOuterHTML(el) {
        if (el.outerHTML) {
            return el.outerHTML;
        } else {
            var container = document.createElement('div');
            container.appendChild(el.cloneNode(true));
            return container.innerHTML;
        }
    }

    var commonTagRE = /^(div|p|span|img|a|b|i|br|ul|ol|li|h1|h2|h3|h4|h5|h6|code|pre|table|th|td|tr|form|label|input|select|option|nav|article|section|header|footer)$/i;
    var reservedTagRE = /^(slot|partial|component)$/i;

    var isUnknownElement = undefined;
    if ('development' !== 'production') {
        isUnknownElement = function(el, tag) {
            if (tag.indexOf('-') > -1) {
                // http://stackoverflow.com/a/28210364/1070244
                return el.constructor === window.HTMLUnknownElement || el.constructor === window.HTMLElement;
            } else {
                return (/HTMLUnknownElement/.test(el.toString()) &&
                    // Chrome returns unknown for several HTML5 elements.
                    // https://code.google.com/p/chromium/issues/detail?id=540526
                    !/^(data|time|rtc|rb)$/.test(tag)
                );
            }
        };
    }

    /**
     * Check if an element is a component, if yes return its
     * component id.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Object|undefined}
     */

    function checkComponentAttr(el, options) {
        var tag = el.tagName.toLowerCase();
        var hasAttrs = el.hasAttributes();
        if (!commonTagRE.test(tag) && !reservedTagRE.test(tag)) {
            if (resolveAsset(options, 'components', tag)) {
                return {
                    id: tag
                };
            } else {
                var is = hasAttrs && getIsBinding(el, options);
                if (is) {
                    return is;
                } else if ('development' !== 'production') {
                    var expectedTag = options._componentNameMap && options._componentNameMap[tag];
                    if (expectedTag) {
                        warn('Unknown custom element: <' + tag + '> - ' + 'did you mean <' + expectedTag + '>? ' + 'HTML is case-insensitive, remember to use kebab-case in templates.');
                    } else if (isUnknownElement(el, tag)) {
                        warn('Unknown custom element: <' + tag + '> - did you ' + 'register the component correctly? For recursive components, ' + 'make sure to provide the "name" option.');
                    }
                }
            }
        } else if (hasAttrs) {
            return getIsBinding(el, options);
        }
    }

    /**
     * Get "is" binding from an element.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Object|undefined}
     */

    function getIsBinding(el, options) {
        // dynamic syntax
        var exp = el.getAttribute('is');
        if (exp != null) {
            if (resolveAsset(options, 'components', exp)) {
                el.removeAttribute('is');
                return {
                    id: exp
                };
            }
        } else {
            exp = getBindAttr(el, 'is');
            if (exp != null) {
                return {
                    id: exp,
                    dynamic: true
                };
            }
        }
    }

    /**
     * Option overwriting strategies are functions that handle
     * how to merge a parent option value and a child option
     * value into the final value.
     *
     * All strategy functions follow the same signature:
     *
     * @param {*} parentVal
     * @param {*} childVal
     * @param {Vue} [vm]
     */

    var strats = config.optionMergeStrategies = Object.create(null);

    /**
     * Helper that recursively merges two data objects together.
     */

    function mergeData(to, from) {
        var key, toVal, fromVal;
        for (key in from) {
            toVal = to[key];
            fromVal = from[key];
            if (!hasOwn(to, key)) {
                set(to, key, fromVal);
            } else if (isObject(toVal) && isObject(fromVal)) {
                mergeData(toVal, fromVal);
            }
        }
        return to;
    }

    /**
     * Data
     */

    strats.data = function(parentVal, childVal, vm) {
        if (!vm) {
            // in a Vue.extend merge, both should be functions
            if (!childVal) {
                return parentVal;
            }
            if (typeof childVal !== 'function') {
                'development' !== 'production' && warn('The "data" option should be a function ' + 'that returns a per-instance value in component ' + 'definitions.', vm);
                return parentVal;
            }
            if (!parentVal) {
                return childVal;
            }
            // when parentVal & childVal are both present,
            // we need to return a function that returns the
            // merged result of both functions... no need to
            // check if parentVal is a function here because
            // it has to be a function to pass previous merges.
            return function mergedDataFn() {
                return mergeData(childVal.call(this), parentVal.call(this));
            };
        } else if (parentVal || childVal) {
            return function mergedInstanceDataFn() {
                // instance merge
                var instanceData = typeof childVal === 'function' ? childVal.call(vm) : childVal;
                var defaultData = typeof parentVal === 'function' ? parentVal.call(vm) : undefined;
                if (instanceData) {
                    return mergeData(instanceData, defaultData);
                } else {
                    return defaultData;
                }
            };
        }
    };

    /**
     * El
     */

    strats.el = function(parentVal, childVal, vm) {
        if (!vm && childVal && typeof childVal !== 'function') {
            'development' !== 'production' && warn('The "el" option should be a function ' + 'that returns a per-instance value in component ' + 'definitions.', vm);
            return;
        }
        var ret = childVal || parentVal;
        // invoke the element factory if this is instance merge
        return vm && typeof ret === 'function' ? ret.call(vm) : ret;
    };

    /**
     * Hooks and param attributes are merged as arrays.
     */

    strats.init = strats.created = strats.ready = strats.attached = strats.detached = strats.beforeCompile = strats.compiled = strats.beforeDestroy = strats.destroyed = strats.activate = function(parentVal, childVal) {
        return childVal ? parentVal ? parentVal.concat(childVal) : isArray(childVal) ? childVal : [childVal] : parentVal;
    };

    /**
     * Assets
     *
     * When a vm is present (instance creation), we need to do
     * a three-way merge between constructor options, instance
     * options and parent options.
     */

    function mergeAssets(parentVal, childVal) {
        var res = Object.create(parentVal || null);
        return childVal ? extend(res, guardArrayAssets(childVal)) : res;
    }

    config._assetTypes.forEach(function(type) {
        strats[type + 's'] = mergeAssets;
    });

    /**
     * Events & Watchers.
     *
     * Events & watchers hashes should not overwrite one
     * another, so we merge them as arrays.
     */

    strats.watch = strats.events = function(parentVal, childVal) {
        if (!childVal) return parentVal;
        if (!parentVal) return childVal;
        var ret = {};
        extend(ret, parentVal);
        for (var key in childVal) {
            var parent = ret[key];
            var child = childVal[key];
            if (parent && !isArray(parent)) {
                parent = [parent];
            }
            ret[key] = parent ? parent.concat(child) : [child];
        }
        return ret;
    };

    /**
     * Other object hashes.
     */

    strats.props = strats.methods = strats.computed = function(parentVal, childVal) {
        if (!childVal) return parentVal;
        if (!parentVal) return childVal;
        var ret = Object.create(null);
        extend(ret, parentVal);
        extend(ret, childVal);
        return ret;
    };

    /**
     * Default strategy.
     */

    var defaultStrat = function defaultStrat(parentVal, childVal) {
        return childVal === undefined ? parentVal : childVal;
    };

    /**
     * Make sure component options get converted to actual
     * constructors.
     *
     * @param {Object} options
     */

    function guardComponents(options) {
        if (options.components) {
            var components = options.components = guardArrayAssets(options.components);
            var ids = Object.keys(components);
            var def;
            if ('development' !== 'production') {
                var map = options._componentNameMap = {};
            }
            for (var i = 0, l = ids.length; i < l; i++) {
                var key = ids[i];
                if (commonTagRE.test(key) || reservedTagRE.test(key)) {
                    'development' !== 'production' && warn('Do not use built-in or reserved HTML elements as component ' + 'id: ' + key);
                    continue;
                }
                // record a all lowercase <-> kebab-case mapping for
                // possible custom element case error warning
                if ('development' !== 'production') {
                    map[key.replace(/-/g, '').toLowerCase()] = hyphenate(key);
                }
                def = components[key];
                if (isPlainObject(def)) {
                    components[key] = Vue.extend(def);
                }
            }
        }
    }

    /**
     * Ensure all props option syntax are normalized into the
     * Object-based format.
     *
     * @param {Object} options
     */

    function guardProps(options) {
        var props = options.props;
        var i, val;
        if (isArray(props)) {
            options.props = {};
            i = props.length;
            while (i--) {
                val = props[i];
                if (typeof val === 'string') {
                    options.props[val] = null;
                } else if (val.name) {
                    options.props[val.name] = val;
                }
            }
        } else if (isPlainObject(props)) {
            var keys = Object.keys(props);
            i = keys.length;
            while (i--) {
                val = props[keys[i]];
                if (typeof val === 'function') {
                    props[keys[i]] = {
                        type: val
                    };
                }
            }
        }
    }

    /**
     * Guard an Array-format assets option and converted it
     * into the key-value Object format.
     *
     * @param {Object|Array} assets
     * @return {Object}
     */

    function guardArrayAssets(assets) {
        if (isArray(assets)) {
            var res = {};
            var i = assets.length;
            var asset;
            while (i--) {
                asset = assets[i];
                var id = typeof asset === 'function' ? asset.options && asset.options.name || asset.id : asset.name || asset.id;
                if (!id) {
                    'development' !== 'production' && warn('Array-syntax assets must provide a "name" or "id" field.');
                } else {
                    res[id] = asset;
                }
            }
            return res;
        }
        return assets;
    }

    /**
     * Merge two option objects into a new one.
     * Core utility used in both instantiation and inheritance.
     *
     * @param {Object} parent
     * @param {Object} child
     * @param {Vue} [vm] - if vm is present, indicates this is
     *                     an instantiation merge.
     */

    function mergeOptions(parent, child, vm) {
        guardComponents(child);
        guardProps(child);
        if ('development' !== 'production') {
            if (child.propsData && !vm) {
                warn('propsData can only be used as an instantiation option.');
            }
        }
        var options = {};
        var key;
        if (child['extends']) {
            parent = typeof child['extends'] === 'function' ? mergeOptions(parent, child['extends'].options, vm) : mergeOptions(parent, child['extends'], vm);
        }
        if (child.mixins) {
            for (var i = 0, l = child.mixins.length; i < l; i++) {
                parent = mergeOptions(parent, child.mixins[i], vm);
            }
        }
        for (key in parent) {
            mergeField(key);
        }
        for (key in child) {
            if (!hasOwn(parent, key)) {
                mergeField(key);
            }
        }

        function mergeField(key) {
            var strat = strats[key] || defaultStrat;
            options[key] = strat(parent[key], child[key], vm, key);
        }
        return options;
    }

    /**
     * Resolve an asset.
     * This function is used because child instances need access
     * to assets defined in its ancestor chain.
     *
     * @param {Object} options
     * @param {String} type
     * @param {String} id
     * @param {Boolean} warnMissing
     * @return {Object|Function}
     */

    function resolveAsset(options, type, id, warnMissing) {
        /* istanbul ignore if */
        if (typeof id !== 'string') {
            return;
        }
        var assets = options[type];
        var camelizedId;
        var res = assets[id] ||
            // camelCase ID
            assets[camelizedId = camelize(id)] ||
            // Pascal Case ID
            assets[camelizedId.charAt(0).toUpperCase() + camelizedId.slice(1)];
        if ('development' !== 'production' && warnMissing && !res) {
            warn('Failed to resolve ' + type.slice(0, -1) + ': ' + id, options);
        }
        return res;
    }

    var uid$1 = 0;

    /**
     * A dep is an observable that can have multiple
     * directives subscribing to it.
     *
     * @constructor
     */
    function Dep() {
        this.id = uid$1++;
        this.subs = [];
    }

    // the current target watcher being evaluated.
    // this is globally unique because there could be only one
    // watcher being evaluated at any time.
    Dep.target = null;

    /**
     * Add a directive subscriber.
     *
     * @param {Directive} sub
     */

    Dep.prototype.addSub = function(sub) {
        this.subs.push(sub);
    };

    /**
     * Remove a directive subscriber.
     *
     * @param {Directive} sub
     */

    Dep.prototype.removeSub = function(sub) {
        this.subs.$remove(sub);
    };

    /**
     * Add self as a dependency to the target watcher.
     */

    Dep.prototype.depend = function() {
        Dep.target.addDep(this);
    };

    /**
     * Notify all subscribers of a new value.
     */

    Dep.prototype.notify = function() {
        // stablize the subscriber list first
        var subs = toArray(this.subs);
        for (var i = 0, l = subs.length; i < l; i++) {
            subs[i].update();
        }
    };

    var arrayProto = Array.prototype;
    var arrayMethods = Object.create(arrayProto)

    /**
     * Intercept mutating methods and emit events
     */

    ;
    ['push', 'pop', 'shift', 'unshift', 'splice', 'sort', 'reverse'].forEach(function(method) {
        // cache original method
        var original = arrayProto[method];
        def(arrayMethods, method, function mutator() {
            // avoid leaking arguments:
            // http://jsperf.com/closure-with-arguments
            var i = arguments.length;
            var args = new Array(i);
            while (i--) {
                args[i] = arguments[i];
            }
            var result = original.apply(this, args);
            var ob = this.__ob__;
            var inserted;
            switch (method) {
                case 'push':
                    inserted = args;
                    break;
                case 'unshift':
                    inserted = args;
                    break;
                case 'splice':
                    inserted = args.slice(2);
                    break;
            }
            if (inserted) ob.observeArray(inserted);
            // notify change
            ob.dep.notify();
            return result;
        });
    });

    /**
     * Swap the element at the given index with a new value
     * and emits corresponding event.
     *
     * @param {Number} index
     * @param {*} val
     * @return {*} - replaced element
     */

    def(arrayProto, '$set', function $set(index, val) {
        if (index >= this.length) {
            this.length = Number(index) + 1;
        }
        return this.splice(index, 1, val)[0];
    });

    /**
     * Convenience method to remove the element at given index or target element reference.
     *
     * @param {*} item
     */

    def(arrayProto, '$remove', function $remove(item) {
        /* istanbul ignore if */
        if (!this.length) return;
        var index = indexOf(this, item);
        if (index > -1) {
            return this.splice(index, 1);
        }
    });

    var arrayKeys = Object.getOwnPropertyNames(arrayMethods);

    /**
     * By default, when a reactive property is set, the new value is
     * also converted to become reactive. However in certain cases, e.g.
     * v-for scope alias and props, we don't want to force conversion
     * because the value may be a nested value under a frozen data structure.
     *
     * So whenever we want to set a reactive property without forcing
     * conversion on the new value, we wrap that call inside this function.
     */

    var shouldConvert = true;

    function withoutConversion(fn) {
        shouldConvert = false;
        fn();
        shouldConvert = true;
    }

    /**
     * Observer class that are attached to each observed
     * object. Once attached, the observer converts target
     * object's property keys into getter/setters that
     * collect dependencies and dispatches updates.
     *
     * @param {Array|Object} value
     * @constructor
     */

    function Observer(value) {
        this.value = value;
        this.dep = new Dep();
        def(value, '__ob__', this);
        if (isArray(value)) {
            var augment = hasProto ? protoAugment : copyAugment;
            augment(value, arrayMethods, arrayKeys);
            this.observeArray(value);
        } else {
            this.walk(value);
        }
    }

    // Instance methods

    /**
     * Walk through each property and convert them into
     * getter/setters. This method should only be called when
     * value type is Object.
     *
     * @param {Object} obj
     */

    Observer.prototype.walk = function(obj) {
        var keys = Object.keys(obj);
        for (var i = 0, l = keys.length; i < l; i++) {
            this.convert(keys[i], obj[keys[i]]);
        }
    };

    /**
     * Observe a list of Array items.
     *
     * @param {Array} items
     */

    Observer.prototype.observeArray = function(items) {
        for (var i = 0, l = items.length; i < l; i++) {
            observe(items[i]);
        }
    };

    /**
     * Convert a property into getter/setter so we can emit
     * the events when the property is accessed/changed.
     *
     * @param {String} key
     * @param {*} val
     */

    Observer.prototype.convert = function(key, val) {
        defineReactive(this.value, key, val);
    };

    /**
     * Add an owner vm, so that when $set/$delete mutations
     * happen we can notify owner vms to proxy the keys and
     * digest the watchers. This is only called when the object
     * is observed as an instance's root $data.
     *
     * @param {Vue} vm
     */

    Observer.prototype.addVm = function(vm) {
        (this.vms || (this.vms = [])).push(vm);
    };

    /**
     * Remove an owner vm. This is called when the object is
     * swapped out as an instance's $data object.
     *
     * @param {Vue} vm
     */

    Observer.prototype.removeVm = function(vm) {
        this.vms.$remove(vm);
    };

    // helpers

    /**
     * Augment an target Object or Array by intercepting
     * the prototype chain using __proto__
     *
     * @param {Object|Array} target
     * @param {Object} src
     */

    function protoAugment(target, src) {
        /* eslint-disable no-proto */
        target.__proto__ = src;
        /* eslint-enable no-proto */
    }

    /**
     * Augment an target Object or Array by defining
     * hidden properties.
     *
     * @param {Object|Array} target
     * @param {Object} proto
     */

    function copyAugment(target, src, keys) {
        for (var i = 0, l = keys.length; i < l; i++) {
            var key = keys[i];
            def(target, key, src[key]);
        }
    }

    /**
     * Attempt to create an observer instance for a value,
     * returns the new observer if successfully observed,
     * or the existing observer if the value already has one.
     *
     * @param {*} value
     * @param {Vue} [vm]
     * @return {Observer|undefined}
     * @static
     */

    function observe(value, vm) {
        if (!value || typeof value !== 'object') {
            return;
        }
        var ob;
        if (hasOwn(value, '__ob__') && value.__ob__ instanceof Observer) {
            ob = value.__ob__;
        } else if (shouldConvert && (isArray(value) || isPlainObject(value)) && Object.isExtensible(value) && !value._isVue) {
            ob = new Observer(value);
        }
        if (ob && vm) {
            ob.addVm(vm);
        }
        return ob;
    }

    /**
     * Define a reactive property on an Object.
     *
     * @param {Object} obj
     * @param {String} key
     * @param {*} val
     */

    function defineReactive(obj, key, val) {
        var dep = new Dep();

        var property = Object.getOwnPropertyDescriptor(obj, key);
        if (property && property.configurable === false) {
            return;
        }

        // cater for pre-defined getter/setters
        var getter = property && property.get;
        var setter = property && property.set;

        var childOb = observe(val);
        Object.defineProperty(obj, key, {
            enumerable: true,
            configurable: true,
            get: function reactiveGetter() {
                var value = getter ? getter.call(obj) : val;
                if (Dep.target) {
                    dep.depend();
                    if (childOb) {
                        childOb.dep.depend();
                    }
                    if (isArray(value)) {
                        for (var e, i = 0, l = value.length; i < l; i++) {
                            e = value[i];
                            e && e.__ob__ && e.__ob__.dep.depend();
                        }
                    }
                }
                return value;
            },
            set: function reactiveSetter(newVal) {
                var value = getter ? getter.call(obj) : val;
                if (newVal === value) {
                    return;
                }
                if (setter) {
                    setter.call(obj, newVal);
                } else {
                    val = newVal;
                }
                childOb = observe(newVal);
                dep.notify();
            }
        });
    }



    var util = Object.freeze({
        defineReactive: defineReactive,
        set: set,
        del: del,
        hasOwn: hasOwn,
        isLiteral: isLiteral,
        isReserved: isReserved,
        _toString: _toString,
        toNumber: toNumber,
        toBoolean: toBoolean,
        stripQuotes: stripQuotes,
        camelize: camelize,
        hyphenate: hyphenate,
        classify: classify,
        bind: bind,
        toArray: toArray,
        extend: extend,
        isObject: isObject,
        isPlainObject: isPlainObject,
        def: def,
        debounce: _debounce,
        indexOf: indexOf,
        cancellable: cancellable,
        looseEqual: looseEqual,
        isArray: isArray,
        hasProto: hasProto,
        inBrowser: inBrowser,
        devtools: devtools,
        isIE9: isIE9,
        isAndroid: isAndroid,
        isIos: isIos,
        isWechat: isWechat,
        get transitionProp() {
            return transitionProp;
        },
        get transitionEndEvent() {
            return transitionEndEvent;
        },
        get animationProp() {
            return animationProp;
        },
        get animationEndEvent() {
            return animationEndEvent;
        },
        nextTick: nextTick,
        get _Set() {
            return _Set;
        },
        query: query,
        inDoc: inDoc,
        getAttr: getAttr,
        getBindAttr: getBindAttr,
        hasBindAttr: hasBindAttr,
        before: before,
        after: after,
        remove: remove,
        prepend: prepend,
        replace: replace,
        on: on,
        off: off,
        setClass: setClass,
        addClass: addClass,
        removeClass: removeClass,
        extractContent: extractContent,
        trimNode: trimNode,
        isTemplate: isTemplate,
        createAnchor: createAnchor,
        findRef: findRef,
        mapNodeRange: mapNodeRange,
        removeNodeRange: removeNodeRange,
        isFragment: isFragment,
        getOuterHTML: getOuterHTML,
        mergeOptions: mergeOptions,
        resolveAsset: resolveAsset,
        checkComponentAttr: checkComponentAttr,
        commonTagRE: commonTagRE,
        reservedTagRE: reservedTagRE,
        get warn() {
            return warn;
        }
    });

    var uid = 0;

    function initMixin(Vue) {
        /**
         * The main init sequence. This is called for every
         * instance, including ones that are created from extended
         * constructors.
         *
         * @param {Object} options - this options object should be
         *                           the result of merging class
         *                           options and the options passed
         *                           in to the constructor.
         */

        Vue.prototype._init = function(options) {
            options = options || {};

            this.$el = null;
            this.$parent = options.parent;
            this.$root = this.$parent ? this.$parent.$root : this;
            this.$children = [];
            this.$refs = {}; // child vm references
            this.$els = {}; // element references
            this._watchers = []; // all watchers as an array
            this._directives = []; // all directives

            // a uid
            this._uid = uid++;

            // a flag to avoid this being observed
            this._isVue = true;

            // events bookkeeping
            this._events = {}; // registered callbacks
            this._eventsCount = {}; // for $broadcast optimization

            // fragment instance properties
            this._isFragment = false;
            this._fragment = // @type {DocumentFragment}
                this._fragmentStart = // @type {Text|Comment}
                this._fragmentEnd = null; // @type {Text|Comment}

            // lifecycle state
            this._isCompiled = this._isDestroyed = this._isReady = this._isAttached = this._isBeingDestroyed = this._vForRemoving = false;
            this._unlinkFn = null;

            // context:
            // if this is a transcluded component, context
            // will be the common parent vm of this instance
            // and its host.
            this._context = options._context || this.$parent;

            // scope:
            // if this is inside an inline v-for, the scope
            // will be the intermediate scope created for this
            // repeat fragment. this is used for linking props
            // and container directives.
            this._scope = options._scope;

            // fragment:
            // if this instance is compiled inside a Fragment, it
            // needs to reigster itself as a child of that fragment
            // for attach/detach to work properly.
            this._frag = options._frag;
            if (this._frag) {
                this._frag.children.push(this);
            }

            // push self into parent / transclusion host
            if (this.$parent) {
                this.$parent.$children.push(this);
            }

            // merge options.
            options = this.$options = mergeOptions(this.constructor.options, options, this);

            // set ref
            this._updateRef();

            // initialize data as empty object.
            // it will be filled up in _initData().
            this._data = {};

            // call init hook
            this._callHook('init');

            // initialize data observation and scope inheritance.
            this._initState();

            // setup event system and option events.
            this._initEvents();

            // call created hook
            this._callHook('created');

            // if `el` option is passed, start compilation.
            if (options.el) {
                this.$mount(options.el);
            }
        };
    }

    var pathCache = new Cache(1000);

    // actions
    var APPEND = 0;
    var PUSH = 1;
    var INC_SUB_PATH_DEPTH = 2;
    var PUSH_SUB_PATH = 3;

    // states
    var BEFORE_PATH = 0;
    var IN_PATH = 1;
    var BEFORE_IDENT = 2;
    var IN_IDENT = 3;
    var IN_SUB_PATH = 4;
    var IN_SINGLE_QUOTE = 5;
    var IN_DOUBLE_QUOTE = 6;
    var AFTER_PATH = 7;
    var ERROR = 8;

    var pathStateMachine = [];

    pathStateMachine[BEFORE_PATH] = {
        'ws': [BEFORE_PATH],
        'ident': [IN_IDENT, APPEND],
        '[': [IN_SUB_PATH],
        'eof': [AFTER_PATH]
    };

    pathStateMachine[IN_PATH] = {
        'ws': [IN_PATH],
        '.': [BEFORE_IDENT],
        '[': [IN_SUB_PATH],
        'eof': [AFTER_PATH]
    };

    pathStateMachine[BEFORE_IDENT] = {
        'ws': [BEFORE_IDENT],
        'ident': [IN_IDENT, APPEND]
    };

    pathStateMachine[IN_IDENT] = {
        'ident': [IN_IDENT, APPEND],
        '0': [IN_IDENT, APPEND],
        'number': [IN_IDENT, APPEND],
        'ws': [IN_PATH, PUSH],
        '.': [BEFORE_IDENT, PUSH],
        '[': [IN_SUB_PATH, PUSH],
        'eof': [AFTER_PATH, PUSH]
    };

    pathStateMachine[IN_SUB_PATH] = {
        "'": [IN_SINGLE_QUOTE, APPEND],
        '"': [IN_DOUBLE_QUOTE, APPEND],
        '[': [IN_SUB_PATH, INC_SUB_PATH_DEPTH],
        ']': [IN_PATH, PUSH_SUB_PATH],
        'eof': ERROR,
        'else': [IN_SUB_PATH, APPEND]
    };

    pathStateMachine[IN_SINGLE_QUOTE] = {
        "'": [IN_SUB_PATH, APPEND],
        'eof': ERROR,
        'else': [IN_SINGLE_QUOTE, APPEND]
    };

    pathStateMachine[IN_DOUBLE_QUOTE] = {
        '"': [IN_SUB_PATH, APPEND],
        'eof': ERROR,
        'else': [IN_DOUBLE_QUOTE, APPEND]
    };

    /**
     * Determine the type of a character in a keypath.
     *
     * @param {Char} ch
     * @return {String} type
     */

    function getPathCharType(ch) {
        if (ch === undefined) {
            return 'eof';
        }

        var code = ch.charCodeAt(0);

        switch (code) {
            case 0x5B: // [
            case 0x5D: // ]
            case 0x2E: // .
            case 0x22: // "
            case 0x27: // '
            case 0x30:
                // 0
                return ch;

            case 0x5F: // _
            case 0x24:
                // $
                return 'ident';

            case 0x20: // Space
            case 0x09: // Tab
            case 0x0A: // Newline
            case 0x0D: // Return
            case 0xA0: // No-break space
            case 0xFEFF: // Byte Order Mark
            case 0x2028: // Line Separator
            case 0x2029:
                // Paragraph Separator
                return 'ws';
        }

        // a-z, A-Z
        if (code >= 0x61 && code <= 0x7A || code >= 0x41 && code <= 0x5A) {
            return 'ident';
        }

        // 1-9
        if (code >= 0x31 && code <= 0x39) {
            return 'number';
        }

        return 'else';
    }

    /**
     * Format a subPath, return its plain form if it is
     * a literal string or number. Otherwise prepend the
     * dynamic indicator (*).
     *
     * @param {String} path
     * @return {String}
     */

    function formatSubPath(path) {
        var trimmed = path.trim();
        // invalid leading 0
        if (path.charAt(0) === '0' && isNaN(path)) {
            return false;
        }
        return isLiteral(trimmed) ? stripQuotes(trimmed) : '*' + trimmed;
    }

    /**
     * Parse a string path into an array of segments
     *
     * @param {String} path
     * @return {Array|undefined}
     */

    function parse(path) {
        var keys = [];
        var index = -1;
        var mode = BEFORE_PATH;
        var subPathDepth = 0;
        var c, newChar, key, type, transition, action, typeMap;

        var actions = [];

        actions[PUSH] = function() {
            if (key !== undefined) {
                keys.push(key);
                key = undefined;
            }
        };

        actions[APPEND] = function() {
            if (key === undefined) {
                key = newChar;
            } else {
                key += newChar;
            }
        };

        actions[INC_SUB_PATH_DEPTH] = function() {
            actions[APPEND]();
            subPathDepth++;
        };

        actions[PUSH_SUB_PATH] = function() {
            if (subPathDepth > 0) {
                subPathDepth--;
                mode = IN_SUB_PATH;
                actions[APPEND]();
            } else {
                subPathDepth = 0;
                key = formatSubPath(key);
                if (key === false) {
                    return false;
                } else {
                    actions[PUSH]();
                }
            }
        };

        function maybeUnescapeQuote() {
            var nextChar = path[index + 1];
            if (mode === IN_SINGLE_QUOTE && nextChar === "'" || mode === IN_DOUBLE_QUOTE && nextChar === '"') {
                index++;
                newChar = '\\' + nextChar;
                actions[APPEND]();
                return true;
            }
        }

        while (mode != null) {
            index++;
            c = path[index];

            if (c === '\\' && maybeUnescapeQuote()) {
                continue;
            }

            type = getPathCharType(c);
            typeMap = pathStateMachine[mode];
            transition = typeMap[type] || typeMap['else'] || ERROR;

            if (transition === ERROR) {
                return; // parse error
            }

            mode = transition[0];
            action = actions[transition[1]];
            if (action) {
                newChar = transition[2];
                newChar = newChar === undefined ? c : newChar;
                if (action() === false) {
                    return;
                }
            }

            if (mode === AFTER_PATH) {
                keys.raw = path;
                return keys;
            }
        }
    }

    /**
     * External parse that check for a cache hit first
     *
     * @param {String} path
     * @return {Array|undefined}
     */

    function parsePath(path) {
        var hit = pathCache.get(path);
        if (!hit) {
            hit = parse(path);
            if (hit) {
                pathCache.put(path, hit);
            }
        }
        return hit;
    }

    /**
     * Get from an object from a path string
     *
     * @param {Object} obj
     * @param {String} path
     */

    function getPath(obj, path) {
        return parseExpression(path).get(obj);
    }

    /**
     * Warn against setting non-existent root path on a vm.
     */

    var warnNonExistent;
    if ('development' !== 'production') {
        warnNonExistent = function(path, vm) {
            warn('You are setting a non-existent path "' + path.raw + '" ' + 'on a vm instance. Consider pre-initializing the property ' + 'with the "data" option for more reliable reactivity ' + 'and better performance.', vm);
        };
    }

    /**
     * Set on an object from a path
     *
     * @param {Object} obj
     * @param {String | Array} path
     * @param {*} val
     */

    function setPath(obj, path, val) {
        var original = obj;
        if (typeof path === 'string') {
            path = parse(path);
        }
        if (!path || !isObject(obj)) {
            return false;
        }
        var last, key;
        for (var i = 0, l = path.length; i < l; i++) {
            last = obj;
            key = path[i];
            if (key.charAt(0) === '*') {
                key = parseExpression(key.slice(1)).get.call(original, original);
            }
            if (i < l - 1) {
                obj = obj[key];
                if (!isObject(obj)) {
                    obj = {};
                    if ('development' !== 'production' && last._isVue) {
                        warnNonExistent(path, last);
                    }
                    set(last, key, obj);
                }
            } else {
                if (isArray(obj)) {
                    obj.$set(key, val);
                } else if (key in obj) {
                    obj[key] = val;
                } else {
                    if ('development' !== 'production' && obj._isVue) {
                        warnNonExistent(path, obj);
                    }
                    set(obj, key, val);
                }
            }
        }
        return true;
    }

    var path = Object.freeze({
        parsePath: parsePath,
        getPath: getPath,
        setPath: setPath
    });

    var expressionCache = new Cache(1000);

    var allowedKeywords = 'Math,Date,this,true,false,null,undefined,Infinity,NaN,' + 'isNaN,isFinite,decodeURI,decodeURIComponent,encodeURI,' + 'encodeURIComponent,parseInt,parseFloat';
    var allowedKeywordsRE = new RegExp('^(' + allowedKeywords.replace(/,/g, '\\b|') + '\\b)');

    // keywords that don't make sense inside expressions
    var improperKeywords = 'break,case,class,catch,const,continue,debugger,default,' + 'delete,do,else,export,extends,finally,for,function,if,' + 'import,in,instanceof,let,return,super,switch,throw,try,' + 'var,while,with,yield,enum,await,implements,package,' + 'protected,static,interface,private,public';
    var improperKeywordsRE = new RegExp('^(' + improperKeywords.replace(/,/g, '\\b|') + '\\b)');

    var wsRE = /\s/g;
    var newlineRE = /\n/g;
    var saveRE = /[\{,]\s*[\w\$_]+\s*:|('(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\]|\\.)*`|`(?:[^`\\]|\\.)*`)|new |typeof |void /g;
    var restoreRE = /"(\d+)"/g;
    var pathTestRE = /^[A-Za-z_$][\w$]*(?:\.[A-Za-z_$][\w$]*|\['.*?'\]|\[".*?"\]|\[\d+\]|\[[A-Za-z_$][\w$]*\])*$/;
    var identRE = /[^\w$\.](?:[A-Za-z_$][\w$]*)/g;
    var booleanLiteralRE = /^(?:true|false)$/;

    /**
     * Save / Rewrite / Restore
     *
     * When rewriting paths found in an expression, it is
     * possible for the same letter sequences to be found in
     * strings and Object literal property keys. Therefore we
     * remove and store these parts in a temporary array, and
     * restore them after the path rewrite.
     */

    var saved = [];

    /**
     * Save replacer
     *
     * The save regex can match two possible cases:
     * 1. An opening object literal
     * 2. A string
     * If matched as a plain string, we need to escape its
     * newlines, since the string needs to be preserved when
     * generating the function body.
     *
     * @param {String} str
     * @param {String} isString - str if matched as a string
     * @return {String} - placeholder with index
     */

    function save(str, isString) {
        var i = saved.length;
        saved[i] = isString ? str.replace(newlineRE, '\\n') : str;
        return '"' + i + '"';
    }

    /**
     * Path rewrite replacer
     *
     * @param {String} raw
     * @return {String}
     */

    function rewrite(raw) {
        var c = raw.charAt(0);
        var path = raw.slice(1);
        if (allowedKeywordsRE.test(path)) {
            return raw;
        } else {
            path = path.indexOf('"') > -1 ? path.replace(restoreRE, restore) : path;
            return c + 'scope.' + path;
        }
    }

    /**
     * Restore replacer
     *
     * @param {String} str
     * @param {String} i - matched save index
     * @return {String}
     */

    function restore(str, i) {
        return saved[i];
    }

    /**
     * Rewrite an expression, prefixing all path accessors with
     * `scope.` and generate getter/setter functions.
     *
     * @param {String} exp
     * @return {Function}
     */

    function compileGetter(exp) {
        if (improperKeywordsRE.test(exp)) {
            'development' !== 'production' && warn('Avoid using reserved keywords in expression: ' + exp);
        }
        // reset state
        saved.length = 0;
        // save strings and object literal keys
        var body = exp.replace(saveRE, save).replace(wsRE, '');
        // rewrite all paths
        // pad 1 space here becaue the regex matches 1 extra char
        body = (' ' + body).replace(identRE, rewrite).replace(restoreRE, restore);
        return makeGetterFn(body);
    }

    /**
     * Build a getter function. Requires eval.
     *
     * We isolate the try/catch so it doesn't affect the
     * optimization of the parse function when it is not called.
     *
     * @param {String} body
     * @return {Function|undefined}
     */

    function makeGetterFn(body) {
        try {
            /* eslint-disable no-new-func */
            return new Function('scope', 'return ' + body + ';');
            /* eslint-enable no-new-func */
        } catch (e) {
            'development' !== 'production' && warn('Invalid expression. ' + 'Generated function body: ' + body);
        }
    }

    /**
     * Compile a setter function for the expression.
     *
     * @param {String} exp
     * @return {Function|undefined}
     */

    function compileSetter(exp) {
        var path = parsePath(exp);
        if (path) {
            return function(scope, val) {
                setPath(scope, path, val);
            };
        } else {
            'development' !== 'production' && warn('Invalid setter expression: ' + exp);
        }
    }

    /**
     * Parse an expression into re-written getter/setters.
     *
     * @param {String} exp
     * @param {Boolean} needSet
     * @return {Function}
     */

    function parseExpression(exp, needSet) {
        exp = exp.trim();
        // try cache
        var hit = expressionCache.get(exp);
        if (hit) {
            if (needSet && !hit.set) {
                hit.set = compileSetter(hit.exp);
            }
            return hit;
        }
        var res = {
            exp: exp
        };
        res.get = isSimplePath(exp) && exp.indexOf('[') < 0
            // optimized super simple getter
            ? makeGetterFn('scope.' + exp)
            // dynamic getter
            : compileGetter(exp);
        if (needSet) {
            res.set = compileSetter(exp);
        }
        expressionCache.put(exp, res);
        return res;
    }

    /**
     * Check if an expression is a simple path.
     *
     * @param {String} exp
     * @return {Boolean}
     */

    function isSimplePath(exp) {
        return pathTestRE.test(exp) &&
            // don't treat true/false as paths
            !booleanLiteralRE.test(exp) &&
            // Math constants e.g. Math.PI, Math.E etc.
            exp.slice(0, 5) !== 'Math.';
    }

    var expression = Object.freeze({
        parseExpression: parseExpression,
        isSimplePath: isSimplePath
    });

    // we have two separate queues: one for directive updates
    // and one for user watcher registered via $watch().
    // we want to guarantee directive updates to be called
    // before user watchers so that when user watchers are
    // triggered, the DOM would have already been in updated
    // state.

    var queue = [];
    var userQueue = [];
    var has = {};
    var circular = {};
    var waiting = false;

    /**
     * Reset the batcher's state.
     */

    function resetBatcherState() {
        queue.length = 0;
        userQueue.length = 0;
        has = {};
        circular = {};
        waiting = false;
    }

    /**
     * Flush both queues and run the watchers.
     */

    function flushBatcherQueue() {
        var _again = true;

        _function: while (_again) {
            _again = false;

            runBatcherQueue(queue);
            runBatcherQueue(userQueue);
            // user watchers triggered more watchers,
            // keep flushing until it depletes
            if (queue.length) {
                _again = true;
                continue _function;
            }
            // dev tool hook
            /* istanbul ignore if */
            if (devtools && config.devtools) {
                devtools.emit('flush');
            }
            resetBatcherState();
        }
    }

    /**
     * Run the watchers in a single queue.
     *
     * @param {Array} queue
     */

    function runBatcherQueue(queue) {
        // do not cache length because more watchers might be pushed
        // as we run existing watchers
        for (var i = 0; i < queue.length; i++) {
            var watcher = queue[i];
            var id = watcher.id;
            has[id] = null;
            watcher.run();
            // in dev build, check and stop circular updates.
            if ('development' !== 'production' && has[id] != null) {
                circular[id] = (circular[id] || 0) + 1;
                if (circular[id] > config._maxUpdateCount) {
                    warn('You may have an infinite update loop for watcher ' + 'with expression "' + watcher.expression + '"', watcher.vm);
                    break;
                }
            }
        }
        queue.length = 0;
    }

    /**
     * Push a watcher into the watcher queue.
     * Jobs with duplicate IDs will be skipped unless it's
     * pushed when the queue is being flushed.
     *
     * @param {Watcher} watcher
     *   properties:
     *   - {Number} id
     *   - {Function} run
     */

    function pushWatcher(watcher) {
        var id = watcher.id;
        if (has[id] == null) {
            // push watcher into appropriate queue
            var q = watcher.user ? userQueue : queue;
            has[id] = q.length;
            q.push(watcher);
            // queue the flush
            if (!waiting) {
                waiting = true;
                nextTick(flushBatcherQueue);
            }
        }
    }

    var uid$2 = 0;

    /**
     * A watcher parses an expression, collects dependencies,
     * and fires callback when the expression value changes.
     * This is used for both the $watch() api and directives.
     *
     * @param {Vue} vm
     * @param {String|Function} expOrFn
     * @param {Function} cb
     * @param {Object} options
     *                 - {Array} filters
     *                 - {Boolean} twoWay
     *                 - {Boolean} deep
     *                 - {Boolean} user
     *                 - {Boolean} sync
     *                 - {Boolean} lazy
     *                 - {Function} [preProcess]
     *                 - {Function} [postProcess]
     * @constructor
     */
    function Watcher(vm, expOrFn, cb, options) {
        // mix in options
        if (options) {
            extend(this, options);
        }
        var isFn = typeof expOrFn === 'function';
        this.vm = vm;
        vm._watchers.push(this);
        this.expression = expOrFn;
        this.cb = cb;
        this.id = ++uid$2; // uid for batching
        this.active = true;
        this.dirty = this.lazy; // for lazy watchers
        this.deps = [];
        this.newDeps = [];
        this.depIds = new _Set();
        this.newDepIds = new _Set();
        this.prevError = null; // for async error stacks
        // parse expression for getter/setter
        if (isFn) {
            this.getter = expOrFn;
            this.setter = undefined;
        } else {
            var res = parseExpression(expOrFn, this.twoWay);
            this.getter = res.get;
            this.setter = res.set;
        }
        this.value = this.lazy ? undefined : this.get();
        // state for avoiding false triggers for deep and Array
        // watchers during vm._digest()
        this.queued = this.shallow = false;
    }

    /**
     * Evaluate the getter, and re-collect dependencies.
     */

    Watcher.prototype.get = function() {
        this.beforeGet();
        var scope = this.scope || this.vm;
        var value;
        try {
            value = this.getter.call(scope, scope);
        } catch (e) {
            if ('development' !== 'production' && config.warnExpressionErrors) {
                warn('Error when evaluating expression ' + '"' + this.expression + '": ' + e.toString(), this.vm);
            }
        }
        // "touch" every property so they are all tracked as
        // dependencies for deep watching
        if (this.deep) {
            traverse(value);
        }
        if (this.preProcess) {
            value = this.preProcess(value);
        }
        if (this.filters) {
            value = scope._applyFilters(value, null, this.filters, false);
        }
        if (this.postProcess) {
            value = this.postProcess(value);
        }
        this.afterGet();
        return value;
    };

    /**
     * Set the corresponding value with the setter.
     *
     * @param {*} value
     */

    Watcher.prototype.set = function(value) {
        var scope = this.scope || this.vm;
        if (this.filters) {
            value = scope._applyFilters(value, this.value, this.filters, true);
        }
        try {
            this.setter.call(scope, scope, value);
        } catch (e) {
            if ('development' !== 'production' && config.warnExpressionErrors) {
                warn('Error when evaluating setter ' + '"' + this.expression + '": ' + e.toString(), this.vm);
            }
        }
        // two-way sync for v-for alias
        var forContext = scope.$forContext;
        if (forContext && forContext.alias === this.expression) {
            if (forContext.filters) {
                'development' !== 'production' && warn('It seems you are using two-way binding on ' + 'a v-for alias (' + this.expression + '), and the ' + 'v-for has filters. This will not work properly. ' + 'Either remove the filters or use an array of ' + 'objects and bind to object properties instead.', this.vm);
                return;
            }
            forContext._withLock(function() {
                if (scope.$key) {
                    // original is an object
                    forContext.rawValue[scope.$key] = value;
                } else {
                    forContext.rawValue.$set(scope.$index, value);
                }
            });
        }
    };

    /**
     * Prepare for dependency collection.
     */

    Watcher.prototype.beforeGet = function() {
        Dep.target = this;
    };

    /**
     * Add a dependency to this directive.
     *
     * @param {Dep} dep
     */

    Watcher.prototype.addDep = function(dep) {
        var id = dep.id;
        if (!this.newDepIds.has(id)) {
            this.newDepIds.add(id);
            this.newDeps.push(dep);
            if (!this.depIds.has(id)) {
                dep.addSub(this);
            }
        }
    };

    /**
     * Clean up for dependency collection.
     */

    Watcher.prototype.afterGet = function() {
        Dep.target = null;
        var i = this.deps.length;
        while (i--) {
            var dep = this.deps[i];
            if (!this.newDepIds.has(dep.id)) {
                dep.removeSub(this);
            }
        }
        var tmp = this.depIds;
        this.depIds = this.newDepIds;
        this.newDepIds = tmp;
        this.newDepIds.clear();
        tmp = this.deps;
        this.deps = this.newDeps;
        this.newDeps = tmp;
        this.newDeps.length = 0;
    };

    /**
     * Subscriber interface.
     * Will be called when a dependency changes.
     *
     * @param {Boolean} shallow
     */

    Watcher.prototype.update = function(shallow) {
        if (this.lazy) {
            this.dirty = true;
        } else if (this.sync || !config.async) {
            this.run();
        } else {
            // if queued, only overwrite shallow with non-shallow,
            // but not the other way around.
            this.shallow = this.queued ? shallow ? this.shallow : false : !!shallow;
            this.queued = true;
            // record before-push error stack in debug mode
            /* istanbul ignore if */
            if ('development' !== 'production' && config.debug) {
                this.prevError = new Error('[vue] async stack trace');
            }
            pushWatcher(this);
        }
    };

    /**
     * Batcher job interface.
     * Will be called by the batcher.
     */

    Watcher.prototype.run = function() {
        if (this.active) {
            var value = this.get();
            if (value !== this.value ||
                // Deep watchers and watchers on Object/Arrays should fire even
                // when the value is the same, because the value may
                // have mutated; but only do so if this is a
                // non-shallow update (caused by a vm digest).
                (isObject(value) || this.deep) && !this.shallow) {
                // set new value
                var oldValue = this.value;
                this.value = value;
                // in debug + async mode, when a watcher callbacks
                // throws, we also throw the saved before-push error
                // so the full cross-tick stack trace is available.
                var prevError = this.prevError;
                /* istanbul ignore if */
                if ('development' !== 'production' && config.debug && prevError) {
                    this.prevError = null;
                    try {
                        this.cb.call(this.vm, value, oldValue);
                    } catch (e) {
                        nextTick(function() {
                            throw prevError;
                        }, 0);
                        throw e;
                    }
                } else {
                    this.cb.call(this.vm, value, oldValue);
                }
            }
            this.queued = this.shallow = false;
        }
    };

    /**
     * Evaluate the value of the watcher.
     * This only gets called for lazy watchers.
     */

    Watcher.prototype.evaluate = function() {
        // avoid overwriting another watcher that is being
        // collected.
        var current = Dep.target;
        this.value = this.get();
        this.dirty = false;
        Dep.target = current;
    };

    /**
     * Depend on all deps collected by this watcher.
     */

    Watcher.prototype.depend = function() {
        var i = this.deps.length;
        while (i--) {
            this.deps[i].depend();
        }
    };

    /**
     * Remove self from all dependencies' subcriber list.
     */

    Watcher.prototype.teardown = function() {
        if (this.active) {
            // remove self from vm's watcher list
            // this is a somewhat expensive operation so we skip it
            // if the vm is being destroyed or is performing a v-for
            // re-render (the watcher list is then filtered by v-for).
            if (!this.vm._isBeingDestroyed && !this.vm._vForRemoving) {
                this.vm._watchers.$remove(this);
            }
            var i = this.deps.length;
            while (i--) {
                this.deps[i].removeSub(this);
            }
            this.active = false;
            this.vm = this.cb = this.value = null;
        }
    };

    /**
     * Recrusively traverse an object to evoke all converted
     * getters, so that every nested property inside the object
     * is collected as a "deep" dependency.
     *
     * @param {*} val
     */

    var seenObjects = new _Set();

    function traverse(val, seen) {
        var i = undefined,
            keys = undefined;
        if (!seen) {
            seen = seenObjects;
            seen.clear();
        }
        var isA = isArray(val);
        var isO = isObject(val);
        if (isA || isO) {
            if (val.__ob__) {
                var depId = val.__ob__.dep.id;
                if (seen.has(depId)) {
                    return;
                } else {
                    seen.add(depId);
                }
            }
            if (isA) {
                i = val.length;
                while (i--) traverse(val[i], seen);
            } else if (isO) {
                keys = Object.keys(val);
                i = keys.length;
                while (i--) traverse(val[keys[i]], seen);
            }
        }
    }

    var text$1 = {

        bind: function bind() {
            this.attr = this.el.nodeType === 3 ? 'data' : 'textContent';
        },

        update: function update(value) {
            this.el[this.attr] = _toString(value);
        }
    };

    var templateCache = new Cache(1000);
    var idSelectorCache = new Cache(1000);

    var map = {
        efault: [0, '', ''],
        legend: [1, '<fieldset>', '</fieldset>'],
        tr: [2, '<table><tbody>', '</tbody></table>'],
        col: [2, '<table><tbody></tbody><colgroup>', '</colgroup></table>']
    };

    map.td = map.th = [3, '<table><tbody><tr>', '</tr></tbody></table>'];

    map.option = map.optgroup = [1, '<select multiple="multiple">', '</select>'];

    map.thead = map.tbody = map.colgroup = map.caption = map.tfoot = [1, '<table>', '</table>'];

    map.g = map.defs = map.symbol = map.use = map.image = map.text = map.circle = map.ellipse = map.line = map.path = map.polygon = map.polyline = map.rect = [1, '<svg ' + 'xmlns="http://www.w3.org/2000/svg" ' + 'xmlns:xlink="http://www.w3.org/1999/xlink" ' + 'xmlns:ev="http://www.w3.org/2001/xml-events"' + 'version="1.1">', '</svg>'];

    /**
     * Check if a node is a supported template node with a
     * DocumentFragment content.
     *
     * @param {Node} node
     * @return {Boolean}
     */

    function isRealTemplate(node) {
        return isTemplate(node) && isFragment(node.content);
    }

    var tagRE$1 = /<([\w:-]+)/;
    var entityRE = /&#?\w+?;/;

    /**
     * Convert a string template to a DocumentFragment.
     * Determines correct wrapping by tag types. Wrapping
     * strategy found in jQuery & component/domify.
     *
     * @param {String} templateString
     * @param {Boolean} raw
     * @return {DocumentFragment}
     */

    function stringToFragment(templateString, raw) {
        // try a cache hit first
        var cacheKey = raw ? templateString : templateString.trim();
        var hit = templateCache.get(cacheKey);
        if (hit) {
            return hit;
        }

        var frag = document.createDocumentFragment();
        var tagMatch = templateString.match(tagRE$1);
        var entityMatch = entityRE.test(templateString);

        if (!tagMatch && !entityMatch) {
            // text only, return a single text node.
            frag.appendChild(document.createTextNode(templateString));
        } else {
            var tag = tagMatch && tagMatch[1];
            var wrap = map[tag] || map.efault;
            var depth = wrap[0];
            var prefix = wrap[1];
            var suffix = wrap[2];
            var node = document.createElement('div');

            node.innerHTML = prefix + templateString + suffix;
            while (depth--) {
                node = node.lastChild;
            }

            var child;
            /* eslint-disable no-cond-assign */
            while (child = node.firstChild) {
                /* eslint-enable no-cond-assign */
                frag.appendChild(child);
            }
        }
        if (!raw) {
            trimNode(frag);
        }
        templateCache.put(cacheKey, frag);
        return frag;
    }

    /**
     * Convert a template node to a DocumentFragment.
     *
     * @param {Node} node
     * @return {DocumentFragment}
     */

    function nodeToFragment(node) {
        // if its a template tag and the browser supports it,
        // its content is already a document fragment. However, iOS Safari has
        // bug when using directly cloned template content with touch
        // events and can cause crashes when the nodes are removed from DOM, so we
        // have to treat template elements as string templates. (#2805)
        /* istanbul ignore if */
        if (isRealTemplate(node)) {
            return stringToFragment(node.innerHTML);
        }
        // script template
        if (node.tagName === 'SCRIPT') {
            return stringToFragment(node.textContent);
        }
        // normal node, clone it to avoid mutating the original
        var clonedNode = cloneNode(node);
        var frag = document.createDocumentFragment();
        var child;
        /* eslint-disable no-cond-assign */
        while (child = clonedNode.firstChild) {
            /* eslint-enable no-cond-assign */
            frag.appendChild(child);
        }
        trimNode(frag);
        return frag;
    }

    // Test for the presence of the Safari template cloning bug
    // https://bugs.webkit.org/showug.cgi?id=137755
    var hasBrokenTemplate = (function() {
        /* istanbul ignore else */
        if (inBrowser) {
            var a = document.createElement('div');
            a.innerHTML = '<template>1</template>';
            return !a.cloneNode(true).firstChild.innerHTML;
        } else {
            return false;
        }
    })();

    // Test for IE10/11 textarea placeholder clone bug
    var hasTextareaCloneBug = (function() {
        /* istanbul ignore else */
        if (inBrowser) {
            var t = document.createElement('textarea');
            t.placeholder = 't';
            return t.cloneNode(true).value === 't';
        } else {
            return false;
        }
    })();

    /**
     * 1. Deal with Safari cloning nested <template> bug by
     *    manually cloning all template instances.
     * 2. Deal with IE10/11 textarea placeholder bug by setting
     *    the correct value after cloning.
     *
     * @param {Element|DocumentFragment} node
     * @return {Element|DocumentFragment}
     */

    function cloneNode(node) {
        /* istanbul ignore if */
        if (!node.querySelectorAll) {
            return node.cloneNode();
        }
        var res = node.cloneNode(true);
        var i, original, cloned;
        /* istanbul ignore if */
        if (hasBrokenTemplate) {
            var tempClone = res;
            if (isRealTemplate(node)) {
                node = node.content;
                tempClone = res.content;
            }
            original = node.querySelectorAll('template');
            if (original.length) {
                cloned = tempClone.querySelectorAll('template');
                i = cloned.length;
                while (i--) {
                    cloned[i].parentNode.replaceChild(cloneNode(original[i]), cloned[i]);
                }
            }
        }
        /* istanbul ignore if */
        if (hasTextareaCloneBug) {
            if (node.tagName === 'TEXTAREA') {
                res.value = node.value;
            } else {
                original = node.querySelectorAll('textarea');
                if (original.length) {
                    cloned = res.querySelectorAll('textarea');
                    i = cloned.length;
                    while (i--) {
                        cloned[i].value = original[i].value;
                    }
                }
            }
        }
        return res;
    }

    /**
     * Process the template option and normalizes it into a
     * a DocumentFragment that can be used as a partial or a
     * instance template.
     *
     * @param {*} template
     *        Possible values include:
     *        - DocumentFragment object
     *        - Node object of type Template
     *        - id selector: '#some-template-id'
     *        - template string: '<div><span>{{msg}}</span></div>'
     * @param {Boolean} shouldClone
     * @param {Boolean} raw
     *        inline HTML interpolation. Do not check for id
     *        selector and keep whitespace in the string.
     * @return {DocumentFragment|undefined}
     */

    function parseTemplate(template, shouldClone, raw) {
        var node, frag;

        // if the template is already a document fragment,
        // do nothing
        if (isFragment(template)) {
            trimNode(template);
            return shouldClone ? cloneNode(template) : template;
        }

        if (typeof template === 'string') {
            // id selector
            if (!raw && template.charAt(0) === '#') {
                // id selector can be cached too
                frag = idSelectorCache.get(template);
                if (!frag) {
                    node = document.getElementById(template.slice(1));
                    if (node) {
                        frag = nodeToFragment(node);
                        // save selector to cache
                        idSelectorCache.put(template, frag);
                    }
                }
            } else {
                // normal string template
                frag = stringToFragment(template, raw);
            }
        } else if (template.nodeType) {
            // a direct node
            frag = nodeToFragment(template);
        }

        return frag && shouldClone ? cloneNode(frag) : frag;
    }

    var template = Object.freeze({
        cloneNode: cloneNode,
        parseTemplate: parseTemplate
    });

    var html = {

        bind: function bind() {
            // a comment node means this is a binding for
            // {{{ inline unescaped html }}}
            if (this.el.nodeType === 8) {
                // hold nodes
                this.nodes = [];
                // replace the placeholder with proper anchor
                this.anchor = createAnchor('v-html');
                replace(this.el, this.anchor);
            }
        },

        update: function update(value) {
            value = _toString(value);
            if (this.nodes) {
                this.swap(value);
            } else {
                this.el.innerHTML = value;
            }
        },

        swap: function swap(value) {
            // remove old nodes
            var i = this.nodes.length;
            while (i--) {
                remove(this.nodes[i]);
            }
            // convert new value to a fragment
            // do not attempt to retrieve from id selector
            var frag = parseTemplate(value, true, true);
            // save a reference to these nodes so we can remove later
            this.nodes = toArray(frag.childNodes);
            before(frag, this.anchor);
        }
    };

    /**
     * Abstraction for a partially-compiled fragment.
     * Can optionally compile content with a child scope.
     *
     * @param {Function} linker
     * @param {Vue} vm
     * @param {DocumentFragment} frag
     * @param {Vue} [host]
     * @param {Object} [scope]
     * @param {Fragment} [parentFrag]
     */
    function Fragment(linker, vm, frag, host, scope, parentFrag) {
        this.children = [];
        this.childFrags = [];
        this.vm = vm;
        this.scope = scope;
        this.inserted = false;
        this.parentFrag = parentFrag;
        if (parentFrag) {
            parentFrag.childFrags.push(this);
        }
        this.unlink = linker(vm, frag, host, scope, this);
        var single = this.single = frag.childNodes.length === 1 &&
            // do not go single mode if the only node is an anchor
            !frag.childNodes[0].__v_anchor;
        if (single) {
            this.node = frag.childNodes[0];
            this.before = singleBefore;
            this.remove = singleRemove;
        } else {
            this.node = createAnchor('fragment-start');
            this.end = createAnchor('fragment-end');
            this.frag = frag;
            prepend(this.node, frag);
            frag.appendChild(this.end);
            this.before = multiBefore;
            this.remove = multiRemove;
        }
        this.node.__v_frag = this;
    }

    /**
     * Call attach/detach for all components contained within
     * this fragment. Also do so recursively for all child
     * fragments.
     *
     * @param {Function} hook
     */

    Fragment.prototype.callHook = function(hook) {
        var i, l;
        for (i = 0, l = this.childFrags.length; i < l; i++) {
            this.childFrags[i].callHook(hook);
        }
        for (i = 0, l = this.children.length; i < l; i++) {
            hook(this.children[i]);
        }
    };

    /**
     * Insert fragment before target, single node version
     *
     * @param {Node} target
     * @param {Boolean} withTransition
     */

    function singleBefore(target, withTransition) {
        this.inserted = true;
        var method = withTransition !== false ? beforeWithTransition : before;
        method(this.node, target, this.vm);
        if (inDoc(this.node)) {
            this.callHook(attach);
        }
    }

    /**
     * Remove fragment, single node version
     */

    function singleRemove() {
        this.inserted = false;
        var shouldCallRemove = inDoc(this.node);
        var self = this;
        this.beforeRemove();
        removeWithTransition(this.node, this.vm, function() {
            if (shouldCallRemove) {
                self.callHook(detach);
            }
            self.destroy();
        });
    }

    /**
     * Insert fragment before target, multi-nodes version
     *
     * @param {Node} target
     * @param {Boolean} withTransition
     */

    function multiBefore(target, withTransition) {
        this.inserted = true;
        var vm = this.vm;
        var method = withTransition !== false ? beforeWithTransition : before;
        mapNodeRange(this.node, this.end, function(node) {
            method(node, target, vm);
        });
        if (inDoc(this.node)) {
            this.callHook(attach);
        }
    }

    /**
     * Remove fragment, multi-nodes version
     */

    function multiRemove() {
        this.inserted = false;
        var self = this;
        var shouldCallRemove = inDoc(this.node);
        this.beforeRemove();
        removeNodeRange(this.node, this.end, this.vm, this.frag, function() {
            if (shouldCallRemove) {
                self.callHook(detach);
            }
            self.destroy();
        });
    }

    /**
     * Prepare the fragment for removal.
     */

    Fragment.prototype.beforeRemove = function() {
        var i, l;
        for (i = 0, l = this.childFrags.length; i < l; i++) {
            // call the same method recursively on child
            // fragments, depth-first
            this.childFrags[i].beforeRemove(false);
        }
        for (i = 0, l = this.children.length; i < l; i++) {
            // Call destroy for all contained instances,
            // with remove:false and defer:true.
            // Defer is necessary because we need to
            // keep the children to call detach hooks
            // on them.
            this.children[i].$destroy(false, true);
        }
        var dirs = this.unlink.dirs;
        for (i = 0, l = dirs.length; i < l; i++) {
            // disable the watchers on all the directives
            // so that the rendered content stays the same
            // during removal.
            dirs[i]._watcher && dirs[i]._watcher.teardown();
        }
    };

    /**
     * Destroy the fragment.
     */

    Fragment.prototype.destroy = function() {
        if (this.parentFrag) {
            this.parentFrag.childFrags.$remove(this);
        }
        this.node.__v_frag = null;
        this.unlink();
    };

    /**
     * Call attach hook for a Vue instance.
     *
     * @param {Vue} child
     */

    function attach(child) {
        if (!child._isAttached && inDoc(child.$el)) {
            child._callHook('attached');
        }
    }

    /**
     * Call detach hook for a Vue instance.
     *
     * @param {Vue} child
     */

    function detach(child) {
        if (child._isAttached && !inDoc(child.$el)) {
            child._callHook('detached');
        }
    }

    var linkerCache = new Cache(5000);

    /**
     * A factory that can be used to create instances of a
     * fragment. Caches the compiled linker if possible.
     *
     * @param {Vue} vm
     * @param {Element|String} el
     */
    function FragmentFactory(vm, el) {
        this.vm = vm;
        var template;
        var isString = typeof el === 'string';
        if (isString || isTemplate(el) && !el.hasAttribute('v-if')) {
            template = parseTemplate(el, true);
        } else {
            template = document.createDocumentFragment();
            template.appendChild(el);
        }
        this.template = template;
        // linker can be cached, but only for components
        var linker;
        var cid = vm.constructor.cid;
        if (cid > 0) {
            var cacheId = cid + (isString ? el : getOuterHTML(el));
            linker = linkerCache.get(cacheId);
            if (!linker) {
                linker = compile(template, vm.$options, true);
                linkerCache.put(cacheId, linker);
            }
        } else {
            linker = compile(template, vm.$options, true);
        }
        this.linker = linker;
    }

    /**
     * Create a fragment instance with given host and scope.
     *
     * @param {Vue} host
     * @param {Object} scope
     * @param {Fragment} parentFrag
     */

    FragmentFactory.prototype.create = function(host, scope, parentFrag) {
        var frag = cloneNode(this.template);
        return new Fragment(this.linker, this.vm, frag, host, scope, parentFrag);
    };

    var ON = 700;
    var MODEL = 800;
    var BIND = 850;
    var TRANSITION = 1100;
    var EL = 1500;
    var COMPONENT = 1500;
    var PARTIAL = 1750;
    var IF = 2100;
    var FOR = 2200;
    var SLOT = 2300;

    var uid$3 = 0;

    var vFor = {

        priority: FOR,
        terminal: true,

        params: ['track-by', 'stagger', 'enter-stagger', 'leave-stagger'],

        bind: function bind() {
            // support "item in/of items" syntax
            var inMatch = this.expression.match(/(.*) (?:in|of) (.*)/);
            if (inMatch) {
                var itMatch = inMatch[1].match(/\((.*),(.*)\)/);
                if (itMatch) {
                    this.iterator = itMatch[1].trim();
                    this.alias = itMatch[2].trim();
                } else {
                    this.alias = inMatch[1].trim();
                }
                this.expression = inMatch[2];
            }

            if (!this.alias) {
                'development' !== 'production' && warn('Invalid v-for expression "' + this.descriptor.raw + '": ' + 'alias is required.', this.vm);
                return;
            }

            // uid as a cache identifier
            this.id = '__v-for__' + ++uid$3;

            // check if this is an option list,
            // so that we know if we need to update the <select>'s
            // v-model when the option list has changed.
            // because v-model has a lower priority than v-for,
            // the v-model is not bound here yet, so we have to
            // retrive it in the actual updateModel() function.
            var tag = this.el.tagName;
            this.isOption = (tag === 'OPTION' || tag === 'OPTGROUP') && this.el.parentNode.tagName === 'SELECT';

            // setup anchor nodes
            this.start = createAnchor('v-for-start');
            this.end = createAnchor('v-for-end');
            replace(this.el, this.end);
            before(this.start, this.end);

            // cache
            this.cache = Object.create(null);

            // fragment factory
            this.factory = new FragmentFactory(this.vm, this.el);
        },

        update: function update(data) {
            this.diff(data);
            this.updateRef();
            this.updateModel();
        },

        /**
         * Diff, based on new data and old data, determine the
         * minimum amount of DOM manipulations needed to make the
         * DOM reflect the new data Array.
         *
         * The algorithm diffs the new data Array by storing a
         * hidden reference to an owner vm instance on previously
         * seen data. This allows us to achieve O(n) which is
         * better than a levenshtein distance based algorithm,
         * which is O(m * n).
         *
         * @param {Array} data
         */

        diff: function diff(data) {
            // check if the Array was converted from an Object
            var item = data[0];
            var convertedFromObject = this.fromObject = isObject(item) && hasOwn(item, '$key') && hasOwn(item, '$value');

            var trackByKey = this.params.trackBy;
            var oldFrags = this.frags;
            var frags = this.frags = new Array(data.length);
            var alias = this.alias;
            var iterator = this.iterator;
            var start = this.start;
            var end = this.end;
            var inDocument = inDoc(start);
            var init = !oldFrags;
            var i, l, frag, key, value, primitive;

            // First pass, go through the new Array and fill up
            // the new frags array. If a piece of data has a cached
            // instance for it, we reuse it. Otherwise build a new
            // instance.
            for (i = 0, l = data.length; i < l; i++) {
                item = data[i];
                key = convertedFromObject ? item.$key : null;
                value = convertedFromObject ? item.$value : item;
                primitive = !isObject(value);
                frag = !init && this.getCachedFrag(value, i, key);
                if (frag) {
                    // reusable fragment
                    frag.reused = true;
                    // update $index
                    frag.scope.$index = i;
                    // update $key
                    if (key) {
                        frag.scope.$key = key;
                    }
                    // update iterator
                    if (iterator) {
                        frag.scope[iterator] = key !== null ? key : i;
                    }
                    // update data for track-by, object repeat &
                    // primitive values.
                    if (trackByKey || convertedFromObject || primitive) {
                        withoutConversion(function() {
                            frag.scope[alias] = value;
                        });
                    }
                } else {
                    // new isntance
                    frag = this.create(value, alias, i, key);
                    frag.fresh = !init;
                }
                frags[i] = frag;
                if (init) {
                    frag.before(end);
                }
            }

            // we're done for the initial render.
            if (init) {
                return;
            }

            // Second pass, go through the old fragments and
            // destroy those who are not reused (and remove them
            // from cache)
            var removalIndex = 0;
            var totalRemoved = oldFrags.length - frags.length;
            // when removing a large number of fragments, watcher removal
            // turns out to be a perf bottleneck, so we batch the watcher
            // removals into a single filter call!
            this.vm._vForRemoving = true;
            for (i = 0, l = oldFrags.length; i < l; i++) {
                frag = oldFrags[i];
                if (!frag.reused) {
                    this.deleteCachedFrag(frag);
                    this.remove(frag, removalIndex++, totalRemoved, inDocument);
                }
            }
            this.vm._vForRemoving = false;
            if (removalIndex) {
                this.vm._watchers = this.vm._watchers.filter(function(w) {
                    return w.active;
                });
            }

            // Final pass, move/insert new fragments into the
            // right place.
            var targetPrev, prevEl, currentPrev;
            var insertionIndex = 0;
            for (i = 0, l = frags.length; i < l; i++) {
                frag = frags[i];
                // this is the frag that we should be after
                targetPrev = frags[i - 1];
                prevEl = targetPrev ? targetPrev.staggerCb ? targetPrev.staggerAnchor : targetPrev.end || targetPrev.node : start;
                if (frag.reused && !frag.staggerCb) {
                    currentPrev = findPrevFrag(frag, start, this.id);
                    if (currentPrev !== targetPrev && (!currentPrev ||
                            // optimization for moving a single item.
                            // thanks to suggestions by @livoras in #1807
                            findPrevFrag(currentPrev, start, this.id) !== targetPrev)) {
                        this.move(frag, prevEl);
                    }
                } else {
                    // new instance, or still in stagger.
                    // insert with updated stagger index.
                    this.insert(frag, insertionIndex++, prevEl, inDocument);
                }
                frag.reused = frag.fresh = false;
            }
        },

        /**
         * Create a new fragment instance.
         *
         * @param {*} value
         * @param {String} alias
         * @param {Number} index
         * @param {String} [key]
         * @return {Fragment}
         */

        create: function create(value, alias, index, key) {
            var host = this._host;
            // create iteration scope
            var parentScope = this._scope || this.vm;
            var scope = Object.create(parentScope);
            // ref holder for the scope
            scope.$refs = Object.create(parentScope.$refs);
            scope.$els = Object.create(parentScope.$els);
            // make sure point $parent to parent scope
            scope.$parent = parentScope;
            // for two-way binding on alias
            scope.$forContext = this;
            // define scope properties
            // important: define the scope alias without forced conversion
            // so that frozen data structures remain non-reactive.
            withoutConversion(function() {
                defineReactive(scope, alias, value);
            });
            defineReactive(scope, '$index', index);
            if (key) {
                defineReactive(scope, '$key', key);
            } else if (scope.$key) {
                // avoid accidental fallback
                def(scope, '$key', null);
            }
            if (this.iterator) {
                defineReactive(scope, this.iterator, key !== null ? key : index);
            }
            var frag = this.factory.create(host, scope, this._frag);
            frag.forId = this.id;
            this.cacheFrag(value, frag, index, key);
            return frag;
        },

        /**
         * Update the v-ref on owner vm.
         */

        updateRef: function updateRef() {
            var ref = this.descriptor.ref;
            if (!ref) return;
            var hash = (this._scope || this.vm).$refs;
            var refs;
            if (!this.fromObject) {
                refs = this.frags.map(findVmFromFrag);
            } else {
                refs = {};
                this.frags.forEach(function(frag) {
                    refs[frag.scope.$key] = findVmFromFrag(frag);
                });
            }
            hash[ref] = refs;
        },

        /**
         * For option lists, update the containing v-model on
         * parent <select>.
         */

        updateModel: function updateModel() {
            if (this.isOption) {
                var parent = this.start.parentNode;
                var model = parent && parent.__v_model;
                if (model) {
                    model.forceUpdate();
                }
            }
        },

        /**
         * Insert a fragment. Handles staggering.
         *
         * @param {Fragment} frag
         * @param {Number} index
         * @param {Node} prevEl
         * @param {Boolean} inDocument
         */

        insert: function insert(frag, index, prevEl, inDocument) {
            if (frag.staggerCb) {
                frag.staggerCb.cancel();
                frag.staggerCb = null;
            }
            var staggerAmount = this.getStagger(frag, index, null, 'enter');
            if (inDocument && staggerAmount) {
                // create an anchor and insert it synchronously,
                // so that we can resolve the correct order without
                // worrying about some elements not inserted yet
                var anchor = frag.staggerAnchor;
                if (!anchor) {
                    anchor = frag.staggerAnchor = createAnchor('stagger-anchor');
                    anchor.__v_frag = frag;
                }
                after(anchor, prevEl);
                var op = frag.staggerCb = cancellable(function() {
                    frag.staggerCb = null;
                    frag.before(anchor);
                    remove(anchor);
                });
                setTimeout(op, staggerAmount);
            } else {
                var target = prevEl.nextSibling;
                /* istanbul ignore if */
                if (!target) {
                    // reset end anchor position in case the position was messed up
                    // by an external drag-n-drop library.
                    after(this.end, prevEl);
                    target = this.end;
                }
                frag.before(target);
            }
        },

        /**
         * Remove a fragment. Handles staggering.
         *
         * @param {Fragment} frag
         * @param {Number} index
         * @param {Number} total
         * @param {Boolean} inDocument
         */

        remove: function remove(frag, index, total, inDocument) {
            if (frag.staggerCb) {
                frag.staggerCb.cancel();
                frag.staggerCb = null;
                // it's not possible for the same frag to be removed
                // twice, so if we have a pending stagger callback,
                // it means this frag is queued for enter but removed
                // before its transition started. Since it is already
                // destroyed, we can just leave it in detached state.
                return;
            }
            var staggerAmount = this.getStagger(frag, index, total, 'leave');
            if (inDocument && staggerAmount) {
                var op = frag.staggerCb = cancellable(function() {
                    frag.staggerCb = null;
                    frag.remove();
                });
                setTimeout(op, staggerAmount);
            } else {
                frag.remove();
            }
        },

        /**
         * Move a fragment to a new position.
         * Force no transition.
         *
         * @param {Fragment} frag
         * @param {Node} prevEl
         */

        move: function move(frag, prevEl) {
            // fix a common issue with Sortable:
            // if prevEl doesn't have nextSibling, this means it's
            // been dragged after the end anchor. Just re-position
            // the end anchor to the end of the container.
            /* istanbul ignore if */
            if (!prevEl.nextSibling) {
                this.end.parentNode.appendChild(this.end);
            }
            frag.before(prevEl.nextSibling, false);
        },

        /**
         * Cache a fragment using track-by or the object key.
         *
         * @param {*} value
         * @param {Fragment} frag
         * @param {Number} index
         * @param {String} [key]
         */

        cacheFrag: function cacheFrag(value, frag, index, key) {
            var trackByKey = this.params.trackBy;
            var cache = this.cache;
            var primitive = !isObject(value);
            var id;
            if (key || trackByKey || primitive) {
                id = getTrackByKey(index, key, value, trackByKey);
                if (!cache[id]) {
                    cache[id] = frag;
                } else if (trackByKey !== '$index') {
                    'development' !== 'production' && this.warnDuplicate(value);
                }
            } else {
                id = this.id;
                if (hasOwn(value, id)) {
                    if (value[id] === null) {
                        value[id] = frag;
                    } else {
                        'development' !== 'production' && this.warnDuplicate(value);
                    }
                } else if (Object.isExtensible(value)) {
                    def(value, id, frag);
                } else if ('development' !== 'production') {
                    warn('Frozen v-for objects cannot be automatically tracked, make sure to ' + 'provide a track-by key.');
                }
            }
            frag.raw = value;
        },

        /**
         * Get a cached fragment from the value/index/key
         *
         * @param {*} value
         * @param {Number} index
         * @param {String} key
         * @return {Fragment}
         */

        getCachedFrag: function getCachedFrag(value, index, key) {
            var trackByKey = this.params.trackBy;
            var primitive = !isObject(value);
            var frag;
            if (key || trackByKey || primitive) {
                var id = getTrackByKey(index, key, value, trackByKey);
                frag = this.cache[id];
            } else {
                frag = value[this.id];
            }
            if (frag && (frag.reused || frag.fresh)) {
                'development' !== 'production' && this.warnDuplicate(value);
            }
            return frag;
        },

        /**
         * Delete a fragment from cache.
         *
         * @param {Fragment} frag
         */

        deleteCachedFrag: function deleteCachedFrag(frag) {
            var value = frag.raw;
            var trackByKey = this.params.trackBy;
            var scope = frag.scope;
            var index = scope.$index;
            // fix #948: avoid accidentally fall through to
            // a parent repeater which happens to have $key.
            var key = hasOwn(scope, '$key') && scope.$key;
            var primitive = !isObject(value);
            if (trackByKey || key || primitive) {
                var id = getTrackByKey(index, key, value, trackByKey);
                this.cache[id] = null;
            } else {
                value[this.id] = null;
                frag.raw = null;
            }
        },

        /**
         * Get the stagger amount for an insertion/removal.
         *
         * @param {Fragment} frag
         * @param {Number} index
         * @param {Number} total
         * @param {String} type
         */

        getStagger: function getStagger(frag, index, total, type) {
            type = type + 'Stagger';
            var trans = frag.node.__v_trans;
            var hooks = trans && trans.hooks;
            var hook = hooks && (hooks[type] || hooks.stagger);
            return hook ? hook.call(frag, index, total) : index * parseInt(this.params[type] || this.params.stagger, 10);
        },

        /**
         * Pre-process the value before piping it through the
         * filters. This is passed to and called by the watcher.
         */

        _preProcess: function _preProcess(value) {
            // regardless of type, store the un-filtered raw value.
            this.rawValue = value;
            return value;
        },

        /**
         * Post-process the value after it has been piped through
         * the filters. This is passed to and called by the watcher.
         *
         * It is necessary for this to be called during the
         * wathcer's dependency collection phase because we want
         * the v-for to update when the source Object is mutated.
         */

        _postProcess: function _postProcess(value) {
            if (isArray(value)) {
                return value;
            } else if (isPlainObject(value)) {
                // convert plain object to array.
                var keys = Object.keys(value);
                var i = keys.length;
                var res = new Array(i);
                var key;
                while (i--) {
                    key = keys[i];
                    res[i] = {
                        $key: key,
                        $value: value[key]
                    };
                }
                return res;
            } else {
                if (typeof value === 'number' && !isNaN(value)) {
                    value = range(value);
                }
                return value || [];
            }
        },

        unbind: function unbind() {
            if (this.descriptor.ref) {
                (this._scope || this.vm).$refs[this.descriptor.ref] = null;
            }
            if (this.frags) {
                var i = this.frags.length;
                var frag;
                while (i--) {
                    frag = this.frags[i];
                    this.deleteCachedFrag(frag);
                    frag.destroy();
                }
            }
        }
    };

    /**
     * Helper to find the previous element that is a fragment
     * anchor. This is necessary because a destroyed frag's
     * element could still be lingering in the DOM before its
     * leaving transition finishes, but its inserted flag
     * should have been set to false so we can skip them.
     *
     * If this is a block repeat, we want to make sure we only
     * return frag that is bound to this v-for. (see #929)
     *
     * @param {Fragment} frag
     * @param {Comment|Text} anchor
     * @param {String} id
     * @return {Fragment}
     */

    function findPrevFrag(frag, anchor, id) {
        var el = frag.node.previousSibling;
        /* istanbul ignore if */
        if (!el) return;
        frag = el.__v_frag;
        while ((!frag || frag.forId !== id || !frag.inserted) && el !== anchor) {
            el = el.previousSibling;
            /* istanbul ignore if */
            if (!el) return;
            frag = el.__v_frag;
        }
        return frag;
    }

    /**
     * Find a vm from a fragment.
     *
     * @param {Fragment} frag
     * @return {Vue|undefined}
     */

    function findVmFromFrag(frag) {
        var node = frag.node;
        // handle multi-node frag
        if (frag.end) {
            while (!node.__vue__ && node !== frag.end && node.nextSibling) {
                node = node.nextSibling;
            }
        }
        return node.__vue__;
    }

    /**
     * Create a range array from given number.
     *
     * @param {Number} n
     * @return {Array}
     */

    function range(n) {
        var i = -1;
        var ret = new Array(Math.floor(n));
        while (++i < n) {
            ret[i] = i;
        }
        return ret;
    }

    /**
     * Get the track by key for an item.
     *
     * @param {Number} index
     * @param {String} key
     * @param {*} value
     * @param {String} [trackByKey]
     */

    function getTrackByKey(index, key, value, trackByKey) {
        return trackByKey ? trackByKey === '$index' ? index : trackByKey.charAt(0).match(/\w/) ? getPath(value, trackByKey) : value[trackByKey] : key || value;
    }

    if ('development' !== 'production') {
        vFor.warnDuplicate = function(value) {
            warn('Duplicate value found in v-for="' + this.descriptor.raw + '": ' + JSON.stringify(value) + '. Use track-by="$index" if ' + 'you are expecting duplicate values.', this.vm);
        };
    }

    var vIf = {

        priority: IF,
        terminal: true,

        bind: function bind() {
            var el = this.el;
            if (!el.__vue__) {
                // check else block
                var next = el.nextElementSibling;
                if (next && getAttr(next, 'v-else') !== null) {
                    remove(next);
                    this.elseEl = next;
                }
                // check main block
                this.anchor = createAnchor('v-if');
                replace(el, this.anchor);
            } else {
                'development' !== 'production' && warn('v-if="' + this.expression + '" cannot be ' + 'used on an instance root element.', this.vm);
                this.invalid = true;
            }
        },

        update: function update(value) {
            if (this.invalid) return;
            if (value) {
                if (!this.frag) {
                    this.insert();
                }
            } else {
                this.remove();
            }
        },

        insert: function insert() {
            if (this.elseFrag) {
                this.elseFrag.remove();
                this.elseFrag = null;
            }
            // lazy init factory
            if (!this.factory) {
                this.factory = new FragmentFactory(this.vm, this.el);
            }
            this.frag = this.factory.create(this._host, this._scope, this._frag);
            this.frag.before(this.anchor);
        },

        remove: function remove() {
            if (this.frag) {
                this.frag.remove();
                this.frag = null;
            }
            if (this.elseEl && !this.elseFrag) {
                if (!this.elseFactory) {
                    this.elseFactory = new FragmentFactory(this.elseEl._context || this.vm, this.elseEl);
                }
                this.elseFrag = this.elseFactory.create(this._host, this._scope, this._frag);
                this.elseFrag.before(this.anchor);
            }
        },

        unbind: function unbind() {
            if (this.frag) {
                this.frag.destroy();
            }
            if (this.elseFrag) {
                this.elseFrag.destroy();
            }
        }
    };

    var show = {

        bind: function bind() {
            // check else block
            var next = this.el.nextElementSibling;
            if (next && getAttr(next, 'v-else') !== null) {
                this.elseEl = next;
            }
        },

        update: function update(value) {
            this.apply(this.el, value);
            if (this.elseEl) {
                this.apply(this.elseEl, !value);
            }
        },

        apply: function apply(el, value) {
            if (inDoc(el)) {
                applyTransition(el, value ? 1 : -1, toggle, this.vm);
            } else {
                toggle();
            }

            function toggle() {
                el.style.display = value ? '' : 'none';
            }
        }
    };

    var text$2 = {

        bind: function bind() {
            var self = this;
            var el = this.el;
            var isRange = el.type === 'range';
            var lazy = this.params.lazy;
            var number = this.params.number;
            var debounce = this.params.debounce;

            // handle composition events.
            //   http://blog.evanyou.me/2014/01/03/composition-event/
            // skip this for Android because it handles composition
            // events quite differently. Android doesn't trigger
            // composition events for language input methods e.g.
            // Chinese, but instead triggers them for spelling
            // suggestions... (see Discussion/#162)
            var composing = false;
            if (!isAndroid && !isRange) {
                this.on('compositionstart', function() {
                    composing = true;
                });
                this.on('compositionend', function() {
                    composing = false;
                    // in IE11 the "compositionend" event fires AFTER
                    // the "input" event, so the input handler is blocked
                    // at the end... have to call it here.
                    //
                    // #1327: in lazy mode this is unecessary.
                    if (!lazy) {
                        self.listener();
                    }
                });
            }

            // prevent messing with the input when user is typing,
            // and force update on blur.
            this.focused = false;
            if (!isRange && !lazy) {
                this.on('focus', function() {
                    self.focused = true;
                });
                this.on('blur', function() {
                    self.focused = false;
                    // do not sync value after fragment removal (#2017)
                    if (!self._frag || self._frag.inserted) {
                        self.rawListener();
                    }
                });
            }

            // Now attach the main listener
            this.listener = this.rawListener = function() {
                if (composing || !self._bound) {
                    return;
                }
                var val = number || isRange ? toNumber(el.value) : el.value;
                self.set(val);
                // force update on next tick to avoid lock & same value
                // also only update when user is not typing
                nextTick(function() {
                    if (self._bound && !self.focused) {
                        self.update(self._watcher.value);
                    }
                });
            };

            // apply debounce
            if (debounce) {
                this.listener = _debounce(this.listener, debounce);
            }

            // Support jQuery events, since jQuery.trigger() doesn't
            // trigger native events in some cases and some plugins
            // rely on $.trigger()
            //
            // We want to make sure if a listener is attached using
            // jQuery, it is also removed with jQuery, that's why
            // we do the check for each directive instance and
            // store that check result on itself. This also allows
            // easier test coverage control by unsetting the global
            // jQuery variable in tests.
            this.hasjQuery = typeof jQuery === 'function';
            if (this.hasjQuery) {
                var method = jQuery.fn.on ? 'on' : 'bind';
                jQuery(el)[method]('change', this.rawListener);
                if (!lazy) {
                    jQuery(el)[method]('input', this.listener);
                }
            } else {
                this.on('change', this.rawListener);
                if (!lazy) {
                    this.on('input', this.listener);
                }
            }

            // IE9 doesn't fire input event on backspace/del/cut
            if (!lazy && isIE9) {
                this.on('cut', function() {
                    nextTick(self.listener);
                });
                this.on('keyup', function(e) {
                    if (e.keyCode === 46 || e.keyCode === 8) {
                        self.listener();
                    }
                });
            }

            // set initial value if present
            if (el.hasAttribute('value') || el.tagName === 'TEXTAREA' && el.value.trim()) {
                this.afterBind = this.listener;
            }
        },

        update: function update(value) {
            this.el.value = _toString(value);
        },

        unbind: function unbind() {
            var el = this.el;
            if (this.hasjQuery) {
                var method = jQuery.fn.off ? 'off' : 'unbind';
                jQuery(el)[method]('change', this.listener);
                jQuery(el)[method]('input', this.listener);
            }
        }
    };

    var radio = {

        bind: function bind() {
            var self = this;
            var el = this.el;

            this.getValue = function() {
                // value overwrite via v-bind:value
                if (el.hasOwnProperty('_value')) {
                    return el._value;
                }
                var val = el.value;
                if (self.params.number) {
                    val = toNumber(val);
                }
                return val;
            };

            this.listener = function() {
                self.set(self.getValue());
            };
            this.on('change', this.listener);

            if (el.hasAttribute('checked')) {
                this.afterBind = this.listener;
            }
        },

        update: function update(value) {
            this.el.checked = looseEqual(value, this.getValue());
        }
    };

    var select = {

        bind: function bind() {
            var self = this;
            var el = this.el;

            // method to force update DOM using latest value.
            this.forceUpdate = function() {
                if (self._watcher) {
                    self.update(self._watcher.get());
                }
            };

            // check if this is a multiple select
            var multiple = this.multiple = el.hasAttribute('multiple');

            // attach listener
            this.listener = function() {
                var value = getValue(el, multiple);
                value = self.params.number ? isArray(value) ? value.map(toNumber) : toNumber(value) : value;
                self.set(value);
            };
            this.on('change', this.listener);

            // if has initial value, set afterBind
            var initValue = getValue(el, multiple, true);
            if (multiple && initValue.length || !multiple && initValue !== null) {
                this.afterBind = this.listener;
            }

            // All major browsers except Firefox resets
            // selectedIndex with value -1 to 0 when the element
            // is appended to a new parent, therefore we have to
            // force a DOM update whenever that happens...
            this.vm.$on('hook:attached', this.forceUpdate);
        },

        update: function update(value) {
            var el = this.el;
            el.selectedIndex = -1;
            var multi = this.multiple && isArray(value);
            var options = el.options;
            var i = options.length;
            var op, val;
            while (i--) {
                op = options[i];
                val = op.hasOwnProperty('_value') ? op._value : op.value;
                /* eslint-disable eqeqeq */
                op.selected = multi ? indexOf$1(value, val) > -1 : looseEqual(value, val);
                /* eslint-enable eqeqeq */
            }
        },

        unbind: function unbind() {
            /* istanbul ignore next */
            this.vm.$off('hook:attached', this.forceUpdate);
        }
    };

    /**
     * Get select value
     *
     * @param {SelectElement} el
     * @param {Boolean} multi
     * @param {Boolean} init
     * @return {Array|*}
     */

    function getValue(el, multi, init) {
        var res = multi ? [] : null;
        var op, val, selected;
        for (var i = 0, l = el.options.length; i < l; i++) {
            op = el.options[i];
            selected = init ? op.hasAttribute('selected') : op.selected;
            if (selected) {
                val = op.hasOwnProperty('_value') ? op._value : op.value;
                if (multi) {
                    res.push(val);
                } else {
                    return val;
                }
            }
        }
        return res;
    }

    /**
     * Native Array.indexOf uses strict equal, but in this
     * case we need to match string/numbers with custom equal.
     *
     * @param {Array} arr
     * @param {*} val
     */

    function indexOf$1(arr, val) {
        var i = arr.length;
        while (i--) {
            if (looseEqual(arr[i], val)) {
                return i;
            }
        }
        return -1;
    }

    var checkbox = {

        bind: function bind() {
            var self = this;
            var el = this.el;

            this.getValue = function() {
                return el.hasOwnProperty('_value') ? el._value : self.params.number ? toNumber(el.value) : el.value;
            };

            function getBooleanValue() {
                var val = el.checked;
                if (val && el.hasOwnProperty('_trueValue')) {
                    return el._trueValue;
                }
                if (!val && el.hasOwnProperty('_falseValue')) {
                    return el._falseValue;
                }
                return val;
            }

            this.listener = function() {
                var model = self._watcher.value;
                if (isArray(model)) {
                    var val = self.getValue();
                    if (el.checked) {
                        if (indexOf(model, val) < 0) {
                            model.push(val);
                        }
                    } else {
                        model.$remove(val);
                    }
                } else {
                    self.set(getBooleanValue());
                }
            };

            this.on('change', this.listener);
            if (el.hasAttribute('checked')) {
                this.afterBind = this.listener;
            }
        },

        update: function update(value) {
            var el = this.el;
            if (isArray(value)) {
                el.checked = indexOf(value, this.getValue()) > -1;
            } else {
                if (el.hasOwnProperty('_trueValue')) {
                    el.checked = looseEqual(value, el._trueValue);
                } else {
                    el.checked = !!value;
                }
            }
        }
    };

    var handlers = {
        text: text$2,
        radio: radio,
        select: select,
        checkbox: checkbox
    };

    var model = {

        priority: MODEL,
        twoWay: true,
        handlers: handlers,
        params: ['lazy', 'number', 'debounce'],

        /**
         * Possible elements:
         *   <select>
         *   <textarea>
         *   <input type="*">
         *     - text
         *     - checkbox
         *     - radio
         *     - number
         */

        bind: function bind() {
            // friendly warning...
            this.checkFilters();
            if (this.hasRead && !this.hasWrite) {
                'development' !== 'production' && warn('It seems you are using a read-only filter with ' + 'v-model="' + this.descriptor.raw + '". ' + 'You might want to use a two-way filter to ensure correct behavior.', this.vm);
            }
            var el = this.el;
            var tag = el.tagName;
            var handler;
            if (tag === 'INPUT') {
                handler = handlers[el.type] || handlers.text;
            } else if (tag === 'SELECT') {
                handler = handlers.select;
            } else if (tag === 'TEXTAREA') {
                handler = handlers.text;
            } else {
                'development' !== 'production' && warn('v-model does not support element type: ' + tag, this.vm);
                return;
            }
            el.__v_model = this;
            handler.bind.call(this);
            this.update = handler.update;
            this._unbind = handler.unbind;
        },

        /**
         * Check read/write filter stats.
         */

        checkFilters: function checkFilters() {
            var filters = this.filters;
            if (!filters) return;
            var i = filters.length;
            while (i--) {
                var filter = resolveAsset(this.vm.$options, 'filters', filters[i].name);
                if (typeof filter === 'function' || filter.read) {
                    this.hasRead = true;
                }
                if (filter.write) {
                    this.hasWrite = true;
                }
            }
        },

        unbind: function unbind() {
            this.el.__v_model = null;
            this._unbind && this._unbind();
        }
    };

    // keyCode aliases
    var keyCodes = {
        esc: 27,
        tab: 9,
        enter: 13,
        space: 32,
        'delete': [8, 46],
        up: 38,
        left: 37,
        right: 39,
        down: 40
    };

    function keyFilter(handler, keys) {
        var codes = keys.map(function(key) {
            var charCode = key.charCodeAt(0);
            if (charCode > 47 && charCode < 58) {
                return parseInt(key, 10);
            }
            if (key.length === 1) {
                charCode = key.toUpperCase().charCodeAt(0);
                if (charCode > 64 && charCode < 91) {
                    return charCode;
                }
            }
            return keyCodes[key];
        });
        codes = [].concat.apply([], codes);
        return function keyHandler(e) {
            if (codes.indexOf(e.keyCode) > -1) {
                return handler.call(this, e);
            }
        };
    }

    function stopFilter(handler) {
        return function stopHandler(e) {
            e.stopPropagation();
            return handler.call(this, e);
        };
    }

    function preventFilter(handler) {
        return function preventHandler(e) {
            e.preventDefault();
            return handler.call(this, e);
        };
    }

    function selfFilter(handler) {
        return function selfHandler(e) {
            if (e.target === e.currentTarget) {
                return handler.call(this, e);
            }
        };
    }

    var on$1 = {

        priority: ON,
        acceptStatement: true,
        keyCodes: keyCodes,

        bind: function bind() {
            // deal with iframes
            if (this.el.tagName === 'IFRAME' && this.arg !== 'load') {
                var self = this;
                this.iframeBind = function() {
                    on(self.el.contentWindow, self.arg, self.handler, self.modifiers.capture);
                };
                this.on('load', this.iframeBind);
            }
        },

        update: function update(handler) {
            // stub a noop for v-on with no value,
            // e.g. @mousedown.prevent
            if (!this.descriptor.raw) {
                handler = function() {};
            }

            if (typeof handler !== 'function') {
                'development' !== 'production' && warn('v-on:' + this.arg + '="' + this.expression + '" expects a function value, ' + 'got ' + handler, this.vm);
                return;
            }

            // apply modifiers
            if (this.modifiers.stop) {
                handler = stopFilter(handler);
            }
            if (this.modifiers.prevent) {
                handler = preventFilter(handler);
            }
            if (this.modifiers.self) {
                handler = selfFilter(handler);
            }
            // key filter
            var keys = Object.keys(this.modifiers).filter(function(key) {
                return key !== 'stop' && key !== 'prevent' && key !== 'self' && key !== 'capture';
            });
            if (keys.length) {
                handler = keyFilter(handler, keys);
            }

            this.reset();
            this.handler = handler;

            if (this.iframeBind) {
                this.iframeBind();
            } else {
                on(this.el, this.arg, this.handler, this.modifiers.capture);
            }
        },

        reset: function reset() {
            var el = this.iframeBind ? this.el.contentWindow : this.el;
            if (this.handler) {
                off(el, this.arg, this.handler);
            }
        },

        unbind: function unbind() {
            this.reset();
        }
    };

    var prefixes = ['-webkit-', '-moz-', '-ms-'];
    var camelPrefixes = ['Webkit', 'Moz', 'ms'];
    var importantRE = /!important;?$/;
    var propCache = Object.create(null);

    var testEl = null;

    var style = {

        deep: true,

        update: function update(value) {
            if (typeof value === 'string') {
                this.el.style.cssText = value;
            } else if (isArray(value)) {
                this.handleObject(value.reduce(extend, {}));
            } else {
                this.handleObject(value || {});
            }
        },

        handleObject: function handleObject(value) {
            // cache object styles so that only changed props
            // are actually updated.
            var cache = this.cache || (this.cache = {});
            var name, val;
            for (name in cache) {
                if (!(name in value)) {
                    this.handleSingle(name, null);
                    delete cache[name];
                }
            }
            for (name in value) {
                val = value[name];
                if (val !== cache[name]) {
                    cache[name] = val;
                    this.handleSingle(name, val);
                }
            }
        },

        handleSingle: function handleSingle(prop, value) {
            prop = normalize(prop);
            if (!prop) return; // unsupported prop
            // cast possible numbers/booleans into strings
            if (value != null) value += '';
            if (value) {
                var isImportant = importantRE.test(value) ? 'important' : '';
                if (isImportant) {
                    /* istanbul ignore if */
                    if ('development' !== 'production') {
                        warn('It\'s probably a bad idea to use !important with inline rules. ' + 'This feature will be deprecated in a future version of Vue.');
                    }
                    value = value.replace(importantRE, '').trim();
                    this.el.style.setProperty(prop.kebab, value, isImportant);
                } else {
                    this.el.style[prop.camel] = value;
                }
            } else {
                this.el.style[prop.camel] = '';
            }
        }

    };

    /**
     * Normalize a CSS property name.
     * - cache result
     * - auto prefix
     * - camelCase -> dash-case
     *
     * @param {String} prop
     * @return {String}
     */

    function normalize(prop) {
        if (propCache[prop]) {
            return propCache[prop];
        }
        var res = prefix(prop);
        propCache[prop] = propCache[res] = res;
        return res;
    }

    /**
     * Auto detect the appropriate prefix for a CSS property.
     * https://gist.github.com/paulirish/523692
     *
     * @param {String} prop
     * @return {String}
     */

    function prefix(prop) {
        prop = hyphenate(prop);
        var camel = camelize(prop);
        var upper = camel.charAt(0).toUpperCase() + camel.slice(1);
        if (!testEl) {
            testEl = document.createElement('div');
        }
        var i = prefixes.length;
        var prefixed;
        if (camel !== 'filter' && camel in testEl.style) {
            return {
                kebab: prop,
                camel: camel
            };
        }
        while (i--) {
            prefixed = camelPrefixes[i] + upper;
            if (prefixed in testEl.style) {
                return {
                    kebab: prefixes[i] + prop,
                    camel: prefixed
                };
            }
        }
    }

    // xlink
    var xlinkNS = 'http://www.w3.org/1999/xlink';
    var xlinkRE = /^xlink:/;

    // check for attributes that prohibit interpolations
    var disallowedInterpAttrRE = /^v-|^:|^@|^(?:is|transition|transition-mode|debounce|track-by|stagger|enter-stagger|leave-stagger)$/;
    // these attributes should also set their corresponding properties
    // because they only affect the initial state of the element
    var attrWithPropsRE = /^(?:value|checked|selected|muted)$/;
    // these attributes expect enumrated values of "true" or "false"
    // but are not boolean attributes
    var enumeratedAttrRE = /^(?:draggable|contenteditable|spellcheck)$/;

    // these attributes should set a hidden property for
    // binding v-model to object values
    var modelProps = {
        value: '_value',
        'true-value': '_trueValue',
        'false-value': '_falseValue'
    };

    var bind$1 = {

        priority: BIND,

        bind: function bind() {
            var attr = this.arg;
            var tag = this.el.tagName;
            // should be deep watch on object mode
            if (!attr) {
                this.deep = true;
            }
            // handle interpolation bindings
            var descriptor = this.descriptor;
            var tokens = descriptor.interp;
            if (tokens) {
                // handle interpolations with one-time tokens
                if (descriptor.hasOneTime) {
                    this.expression = tokensToExp(tokens, this._scope || this.vm);
                }

                // only allow binding on native attributes
                if (disallowedInterpAttrRE.test(attr) || attr === 'name' && (tag === 'PARTIAL' || tag === 'SLOT')) {
                    'development' !== 'production' && warn(attr + '="' + descriptor.raw + '": ' + 'attribute interpolation is not allowed in Vue.js ' + 'directives and special attributes.', this.vm);
                    this.el.removeAttribute(attr);
                    this.invalid = true;
                }

                /* istanbul ignore if */
                if ('development' !== 'production') {
                    var raw = attr + '="' + descriptor.raw + '": ';
                    // warn src
                    if (attr === 'src') {
                        warn(raw + 'interpolation in "src" attribute will cause ' + 'a 404 request. Use v-bind:src instead.', this.vm);
                    }

                    // warn style
                    if (attr === 'style') {
                        warn(raw + 'interpolation in "style" attribute will cause ' + 'the attribute to be discarded in Internet Explorer. ' + 'Use v-bind:style instead.', this.vm);
                    }
                }
            }
        },

        update: function update(value) {
            if (this.invalid) {
                return;
            }
            var attr = this.arg;
            if (this.arg) {
                this.handleSingle(attr, value);
            } else {
                this.handleObject(value || {});
            }
        },

        // share object handler with v-bind:class
        handleObject: style.handleObject,

        handleSingle: function handleSingle(attr, value) {
            var el = this.el;
            var interp = this.descriptor.interp;
            if (this.modifiers.camel) {
                attr = camelize(attr);
            }
            if (!interp && attrWithPropsRE.test(attr) && attr in el) {
                var attrValue = attr === 'value' ? value == null // IE9 will set input.value to "null" for null...
                    ? '' : value : value;

                if (el[attr] !== attrValue) {
                    el[attr] = attrValue;
                }
            }
            // set model props
            var modelProp = modelProps[attr];
            if (!interp && modelProp) {
                el[modelProp] = value;
                // update v-model if present
                var model = el.__v_model;
                if (model) {
                    model.listener();
                }
            }
            // do not set value attribute for textarea
            if (attr === 'value' && el.tagName === 'TEXTAREA') {
                el.removeAttribute(attr);
                return;
            }
            // update attribute
            if (enumeratedAttrRE.test(attr)) {
                el.setAttribute(attr, value ? 'true' : 'false');
            } else if (value != null && value !== false) {
                if (attr === 'class') {
                    // handle edge case #1960:
                    // class interpolation should not overwrite Vue transition class
                    if (el.__v_trans) {
                        value += ' ' + el.__v_trans.id + '-transition';
                    }
                    setClass(el, value);
                } else if (xlinkRE.test(attr)) {
                    el.setAttributeNS(xlinkNS, attr, value === true ? '' : value);
                } else {
                    el.setAttribute(attr, value === true ? '' : value);
                }
            } else {
                el.removeAttribute(attr);
            }
        }
    };

    var el = {

        priority: EL,

        bind: function bind() {
            /* istanbul ignore if */
            if (!this.arg) {
                return;
            }
            var id = this.id = camelize(this.arg);
            var refs = (this._scope || this.vm).$els;
            if (hasOwn(refs, id)) {
                refs[id] = this.el;
            } else {
                defineReactive(refs, id, this.el);
            }
        },

        unbind: function unbind() {
            var refs = (this._scope || this.vm).$els;
            if (refs[this.id] === this.el) {
                refs[this.id] = null;
            }
        }
    };

    var ref = {
        bind: function bind() {
            'development' !== 'production' && warn('v-ref:' + this.arg + ' must be used on a child ' + 'component. Found on <' + this.el.tagName.toLowerCase() + '>.', this.vm);
        }
    };

    var cloak = {
        bind: function bind() {
            var el = this.el;
            this.vm.$once('pre-hook:compiled', function() {
                el.removeAttribute('v-cloak');
            });
        }
    };

    // must export plain object
    var directives = {
        text: text$1,
        html: html,
        'for': vFor,
        'if': vIf,
        show: show,
        model: model,
        on: on$1,
        bind: bind$1,
        el: el,
        ref: ref,
        cloak: cloak
    };

    var vClass = {

        deep: true,

        update: function update(value) {
            if (!value) {
                this.cleanup();
            } else if (typeof value === 'string') {
                this.setClass(value.trim().split(/\s+/));
            } else {
                this.setClass(normalize$1(value));
            }
        },

        setClass: function setClass(value) {
            this.cleanup(value);
            for (var i = 0, l = value.length; i < l; i++) {
                var val = value[i];
                if (val) {
                    apply(this.el, val, addClass);
                }
            }
            this.prevKeys = value;
        },

        cleanup: function cleanup(value) {
            var prevKeys = this.prevKeys;
            if (!prevKeys) return;
            var i = prevKeys.length;
            while (i--) {
                var key = prevKeys[i];
                if (!value || value.indexOf(key) < 0) {
                    apply(this.el, key, removeClass);
                }
            }
        }
    };

    /**
     * Normalize objects and arrays (potentially containing objects)
     * into array of strings.
     *
     * @param {Object|Array<String|Object>} value
     * @return {Array<String>}
     */

    function normalize$1(value) {
        var res = [];
        if (isArray(value)) {
            for (var i = 0, l = value.length; i < l; i++) {
                var _key = value[i];
                if (_key) {
                    if (typeof _key === 'string') {
                        res.push(_key);
                    } else {
                        for (var k in _key) {
                            if (_key[k]) res.push(k);
                        }
                    }
                }
            }
        } else if (isObject(value)) {
            for (var key in value) {
                if (value[key]) res.push(key);
            }
        }
        return res;
    }

    /**
     * Add or remove a class/classes on an element
     *
     * @param {Element} el
     * @param {String} key The class name. This may or may not
     *                     contain a space character, in such a
     *                     case we'll deal with multiple class
     *                     names at once.
     * @param {Function} fn
     */

    function apply(el, key, fn) {
        key = key.trim();
        if (key.indexOf(' ') === -1) {
            fn(el, key);
            return;
        }
        // The key contains one or more space characters.
        // Since a class name doesn't accept such characters, we
        // treat it as multiple classes.
        var keys = key.split(/\s+/);
        for (var i = 0, l = keys.length; i < l; i++) {
            fn(el, keys[i]);
        }
    }

    var component = {

        priority: COMPONENT,

        params: ['keep-alive', 'transition-mode', 'inline-template'],

        /**
         * Setup. Two possible usages:
         *
         * - static:
         *   <comp> or <div v-component="comp">
         *
         * - dynamic:
         *   <component :is="view">
         */

        bind: function bind() {
            if (!this.el.__vue__) {
                // keep-alive cache
                this.keepAlive = this.params.keepAlive;
                if (this.keepAlive) {
                    this.cache = {};
                }
                // check inline-template
                if (this.params.inlineTemplate) {
                    // extract inline template as a DocumentFragment
                    this.inlineTemplate = extractContent(this.el, true);
                }
                // component resolution related state
                this.pendingComponentCb = this.Component = null;
                // transition related state
                this.pendingRemovals = 0;
                this.pendingRemovalCb = null;
                // create a ref anchor
                this.anchor = createAnchor('v-component');
                replace(this.el, this.anchor);
                // remove is attribute.
                // this is removed during compilation, but because compilation is
                // cached, when the component is used elsewhere this attribute
                // will remain at link time.
                this.el.removeAttribute('is');
                this.el.removeAttribute(':is');
                // remove ref, same as above
                if (this.descriptor.ref) {
                    this.el.removeAttribute('v-ref:' + hyphenate(this.descriptor.ref));
                }
                // if static, build right now.
                if (this.literal) {
                    this.setComponent(this.expression);
                }
            } else {
                'development' !== 'production' && warn('cannot mount component "' + this.expression + '" ' + 'on already mounted element: ' + this.el);
            }
        },

        /**
         * Public update, called by the watcher in the dynamic
         * literal scenario, e.g. <component :is="view">
         */

        update: function update(value) {
            if (!this.literal) {
                this.setComponent(value);
            }
        },

        /**
         * Switch dynamic components. May resolve the component
         * asynchronously, and perform transition based on
         * specified transition mode. Accepts a few additional
         * arguments specifically for vue-router.
         *
         * The callback is called when the full transition is
         * finished.
         *
         * @param {String} value
         * @param {Function} [cb]
         */

        setComponent: function setComponent(value, cb) {
            this.invalidatePending();
            if (!value) {
                // just remove current
                this.unbuild(true);
                this.remove(this.childVM, cb);
                this.childVM = null;
            } else {
                var self = this;
                this.resolveComponent(value, function() {
                    self.mountComponent(cb);
                });
            }
        },

        /**
         * Resolve the component constructor to use when creating
         * the child vm.
         *
         * @param {String|Function} value
         * @param {Function} cb
         */

        resolveComponent: function resolveComponent(value, cb) {
            var self = this;
            this.pendingComponentCb = cancellable(function(Component) {
                self.ComponentName = Component.options.name || (typeof value === 'string' ? value : null);
                self.Component = Component;
                cb();
            });
            this.vm._resolveComponent(value, this.pendingComponentCb);
        },

        /**
         * Create a new instance using the current constructor and
         * replace the existing instance. This method doesn't care
         * whether the new component and the old one are actually
         * the same.
         *
         * @param {Function} [cb]
         */

        mountComponent: function mountComponent(cb) {
            // actual mount
            this.unbuild(true);
            var self = this;
            var activateHooks = this.Component.options.activate;
            var cached = this.getCached();
            var newComponent = this.build();
            if (activateHooks && !cached) {
                this.waitingFor = newComponent;
                callActivateHooks(activateHooks, newComponent, function() {
                    if (self.waitingFor !== newComponent) {
                        return;
                    }
                    self.waitingFor = null;
                    self.transition(newComponent, cb);
                });
            } else {
                // update ref for kept-alive component
                if (cached) {
                    newComponent._updateRef();
                }
                this.transition(newComponent, cb);
            }
        },

        /**
         * When the component changes or unbinds before an async
         * constructor is resolved, we need to invalidate its
         * pending callback.
         */

        invalidatePending: function invalidatePending() {
            if (this.pendingComponentCb) {
                this.pendingComponentCb.cancel();
                this.pendingComponentCb = null;
            }
        },

        /**
         * Instantiate/insert a new child vm.
         * If keep alive and has cached instance, insert that
         * instance; otherwise build a new one and cache it.
         *
         * @param {Object} [extraOptions]
         * @return {Vue} - the created instance
         */

        build: function build(extraOptions) {
            var cached = this.getCached();
            if (cached) {
                return cached;
            }
            if (this.Component) {
                // default options
                var options = {
                    name: this.ComponentName,
                    el: cloneNode(this.el),
                    template: this.inlineTemplate,
                    // make sure to add the child with correct parent
                    // if this is a transcluded component, its parent
                    // should be the transclusion host.
                    parent: this._host || this.vm,
                    // if no inline-template, then the compiled
                    // linker can be cached for better performance.
                    _linkerCachable: !this.inlineTemplate,
                    _ref: this.descriptor.ref,
                    _asComponent: true,
                    _isRouterView: this._isRouterView,
                    // if this is a transcluded component, context
                    // will be the common parent vm of this instance
                    // and its host.
                    _context: this.vm,
                    // if this is inside an inline v-for, the scope
                    // will be the intermediate scope created for this
                    // repeat fragment. this is used for linking props
                    // and container directives.
                    _scope: this._scope,
                    // pass in the owner fragment of this component.
                    // this is necessary so that the fragment can keep
                    // track of its contained components in order to
                    // call attach/detach hooks for them.
                    _frag: this._frag
                };
                // extra options
                // in 1.0.0 this is used by vue-router only
                /* istanbul ignore if */
                if (extraOptions) {
                    extend(options, extraOptions);
                }
                var child = new this.Component(options);
                if (this.keepAlive) {
                    this.cache[this.Component.cid] = child;
                }
                /* istanbul ignore if */
                if ('development' !== 'production' && this.el.hasAttribute('transition') && child._isFragment) {
                    warn('Transitions will not work on a fragment instance. ' + 'Template: ' + child.$options.template, child);
                }
                return child;
            }
        },

        /**
         * Try to get a cached instance of the current component.
         *
         * @return {Vue|undefined}
         */

        getCached: function getCached() {
            return this.keepAlive && this.cache[this.Component.cid];
        },

        /**
         * Teardown the current child, but defers cleanup so
         * that we can separate the destroy and removal steps.
         *
         * @param {Boolean} defer
         */

        unbuild: function unbuild(defer) {
            if (this.waitingFor) {
                if (!this.keepAlive) {
                    this.waitingFor.$destroy();
                }
                this.waitingFor = null;
            }
            var child = this.childVM;
            if (!child || this.keepAlive) {
                if (child) {
                    // remove ref
                    child._inactive = true;
                    child._updateRef(true);
                }
                return;
            }
            // the sole purpose of `deferCleanup` is so that we can
            // "deactivate" the vm right now and perform DOM removal
            // later.
            child.$destroy(false, defer);
        },

        /**
         * Remove current destroyed child and manually do
         * the cleanup after removal.
         *
         * @param {Function} cb
         */

        remove: function remove(child, cb) {
            var keepAlive = this.keepAlive;
            if (child) {
                // we may have a component switch when a previous
                // component is still being transitioned out.
                // we want to trigger only one lastest insertion cb
                // when the existing transition finishes. (#1119)
                this.pendingRemovals++;
                this.pendingRemovalCb = cb;
                var self = this;
                child.$remove(function() {
                    self.pendingRemovals--;
                    if (!keepAlive) child._cleanup();
                    if (!self.pendingRemovals && self.pendingRemovalCb) {
                        self.pendingRemovalCb();
                        self.pendingRemovalCb = null;
                    }
                });
            } else if (cb) {
                cb();
            }
        },

        /**
         * Actually swap the components, depending on the
         * transition mode. Defaults to simultaneous.
         *
         * @param {Vue} target
         * @param {Function} [cb]
         */

        transition: function transition(target, cb) {
            var self = this;
            var current = this.childVM;
            // for devtool inspection
            if (current) current._inactive = true;
            target._inactive = false;
            this.childVM = target;
            switch (self.params.transitionMode) {
                case 'in-out':
                    target.$before(self.anchor, function() {
                        self.remove(current, cb);
                    });
                    break;
                case 'out-in':
                    self.remove(current, function() {
                        target.$before(self.anchor, cb);
                    });
                    break;
                default:
                    self.remove(current);
                    target.$before(self.anchor, cb);
            }
        },

        /**
         * Unbind.
         */

        unbind: function unbind() {
            this.invalidatePending();
            // Do not defer cleanup when unbinding
            this.unbuild();
            // destroy all keep-alive cached instances
            if (this.cache) {
                for (var key in this.cache) {
                    this.cache[key].$destroy();
                }
                this.cache = null;
            }
        }
    };

    /**
     * Call activate hooks in order (asynchronous)
     *
     * @param {Array} hooks
     * @param {Vue} vm
     * @param {Function} cb
     */

    function callActivateHooks(hooks, vm, cb) {
        var total = hooks.length;
        var called = 0;
        hooks[0].call(vm, next);

        function next() {
            if (++called >= total) {
                cb();
            } else {
                hooks[called].call(vm, next);
            }
        }
    }

    var propBindingModes = config._propBindingModes;
    var empty = {};

    // regexes
    var identRE$1 = /^[$_a-zA-Z]+[\w$]*$/;
    var settablePathRE = /^[A-Za-z_$][\w$]*(\.[A-Za-z_$][\w$]*|\[[^\[\]]+\])*$/;

    /**
     * Compile props on a root element and return
     * a props link function.
     *
     * @param {Element|DocumentFragment} el
     * @param {Array} propOptions
     * @param {Vue} vm
     * @return {Function} propsLinkFn
     */

    function compileProps(el, propOptions, vm) {
        var props = [];
        var names = Object.keys(propOptions);
        var i = names.length;
        var options, name, attr, value, path, parsed, prop;
        while (i--) {
            name = names[i];
            options = propOptions[name] || empty;

            if ('development' !== 'production' && name === '$data') {
                warn('Do not use $data as prop.', vm);
                continue;
            }

            // props could contain dashes, which will be
            // interpreted as minus calculations by the parser
            // so we need to camelize the path here
            path = camelize(name);
            if (!identRE$1.test(path)) {
                'development' !== 'production' && warn('Invalid prop key: "' + name + '". Prop keys ' + 'must be valid identifiers.', vm);
                continue;
            }

            prop = {
                name: name,
                path: path,
                options: options,
                mode: propBindingModes.ONE_WAY,
                raw: null
            };

            attr = hyphenate(name);
            // first check dynamic version
            if ((value = getBindAttr(el, attr)) === null) {
                if ((value = getBindAttr(el, attr + '.sync')) !== null) {
                    prop.mode = propBindingModes.TWO_WAY;
                } else if ((value = getBindAttr(el, attr + '.once')) !== null) {
                    prop.mode = propBindingModes.ONE_TIME;
                }
            }
            if (value !== null) {
                // has dynamic binding!
                prop.raw = value;
                parsed = parseDirective(value);
                value = parsed.expression;
                prop.filters = parsed.filters;
                // check binding type
                if (isLiteral(value) && !parsed.filters) {
                    // for expressions containing literal numbers and
                    // booleans, there's no need to setup a prop binding,
                    // so we can optimize them as a one-time set.
                    prop.optimizedLiteral = true;
                } else {
                    prop.dynamic = true;
                    // check non-settable path for two-way bindings
                    if ('development' !== 'production' && prop.mode === propBindingModes.TWO_WAY && !settablePathRE.test(value)) {
                        prop.mode = propBindingModes.ONE_WAY;
                        warn('Cannot bind two-way prop with non-settable ' + 'parent path: ' + value, vm);
                    }
                }
                prop.parentPath = value;

                // warn required two-way
                if ('development' !== 'production' && options.twoWay && prop.mode !== propBindingModes.TWO_WAY) {
                    warn('Prop "' + name + '" expects a two-way binding type.', vm);
                }
            } else if ((value = getAttr(el, attr)) !== null) {
                // has literal binding!
                prop.raw = value;
            } else if ('development' !== 'production') {
                // check possible camelCase prop usage
                var lowerCaseName = path.toLowerCase();
                value = /[A-Z\-]/.test(name) && (el.getAttribute(lowerCaseName) || el.getAttribute(':' + lowerCaseName) || el.getAttribute('v-bind:' + lowerCaseName) || el.getAttribute(':' + lowerCaseName + '.once') || el.getAttribute('v-bind:' + lowerCaseName + '.once') || el.getAttribute(':' + lowerCaseName + '.sync') || el.getAttribute('v-bind:' + lowerCaseName + '.sync'));
                if (value) {
                    warn('Possible usage error for prop `' + lowerCaseName + '` - ' + 'did you mean `' + attr + '`? HTML is case-insensitive, remember to use ' + 'kebab-case for props in templates.', vm);
                } else if (options.required) {
                    // warn missing required
                    warn('Missing required prop: ' + name, vm);
                }
            }
            // push prop
            props.push(prop);
        }
        return makePropsLinkFn(props);
    }

    /**
     * Build a function that applies props to a vm.
     *
     * @param {Array} props
     * @return {Function} propsLinkFn
     */

    function makePropsLinkFn(props) {
        return function propsLinkFn(vm, scope) {
            // store resolved props info
            vm._props = {};
            var inlineProps = vm.$options.propsData;
            var i = props.length;
            var prop, path, options, value, raw;
            while (i--) {
                prop = props[i];
                raw = prop.raw;
                path = prop.path;
                options = prop.options;
                vm._props[path] = prop;
                if (inlineProps && hasOwn(inlineProps, path)) {
                    initProp(vm, prop, inlineProps[path]);
                }
                if (raw === null) {
                    // initialize absent prop
                    initProp(vm, prop, undefined);
                } else if (prop.dynamic) {
                    // dynamic prop
                    if (prop.mode === propBindingModes.ONE_TIME) {
                        // one time binding
                        value = (scope || vm._context || vm).$get(prop.parentPath);
                        initProp(vm, prop, value);
                    } else {
                        if (vm._context) {
                            // dynamic binding
                            vm._bindDir({
                                name: 'prop',
                                def: propDef,
                                prop: prop
                            }, null, null, scope); // el, host, scope
                        } else {
                            // root instance
                            initProp(vm, prop, vm.$get(prop.parentPath));
                        }
                    }
                } else if (prop.optimizedLiteral) {
                    // optimized literal, cast it and just set once
                    var stripped = stripQuotes(raw);
                    value = stripped === raw ? toBoolean(toNumber(raw)) : stripped;
                    initProp(vm, prop, value);
                } else {
                    // string literal, but we need to cater for
                    // Boolean props with no value, or with same
                    // literal value (e.g. disabled="disabled")
                    // see https://github.com/vuejs/vue-loader/issues/182
                    value = options.type === Boolean && (raw === '' || raw === hyphenate(prop.name)) ? true : raw;
                    initProp(vm, prop, value);
                }
            }
        };
    }

    /**
     * Process a prop with a rawValue, applying necessary coersions,
     * default values & assertions and call the given callback with
     * processed value.
     *
     * @param {Vue} vm
     * @param {Object} prop
     * @param {*} rawValue
     * @param {Function} fn
     */

    function processPropValue(vm, prop, rawValue, fn) {
        var isSimple = prop.dynamic && isSimplePath(prop.parentPath);
        var value = rawValue;
        if (value === undefined) {
            value = getPropDefaultValue(vm, prop);
        }
        value = coerceProp(prop, value);
        var coerced = value !== rawValue;
        if (!assertProp(prop, value, vm)) {
            value = undefined;
        }
        if (isSimple && !coerced) {
            withoutConversion(function() {
                fn(value);
            });
        } else {
            fn(value);
        }
    }

    /**
     * Set a prop's initial value on a vm and its data object.
     *
     * @param {Vue} vm
     * @param {Object} prop
     * @param {*} value
     */

    function initProp(vm, prop, value) {
        processPropValue(vm, prop, value, function(value) {
            defineReactive(vm, prop.path, value);
        });
    }

    /**
     * Update a prop's value on a vm.
     *
     * @param {Vue} vm
     * @param {Object} prop
     * @param {*} value
     */

    function updateProp(vm, prop, value) {
        processPropValue(vm, prop, value, function(value) {
            vm[prop.path] = value;
        });
    }

    /**
     * Get the default value of a prop.
     *
     * @param {Vue} vm
     * @param {Object} prop
     * @return {*}
     */

    function getPropDefaultValue(vm, prop) {
        // no default, return undefined
        var options = prop.options;
        if (!hasOwn(options, 'default')) {
            // absent boolean value defaults to false
            return options.type === Boolean ? false : undefined;
        }
        var def = options['default'];
        // warn against non-factory defaults for Object & Array
        if (isObject(def)) {
            'development' !== 'production' && warn('Invalid default value for prop "' + prop.name + '": ' + 'Props with type Object/Array must use a factory function ' + 'to return the default value.', vm);
        }
        // call factory function for non-Function types
        return typeof def === 'function' && options.type !== Function ? def.call(vm) : def;
    }

    /**
     * Assert whether a prop is valid.
     *
     * @param {Object} prop
     * @param {*} value
     * @param {Vue} vm
     */

    function assertProp(prop, value, vm) {
        if (!prop.options.required && ( // non-required
                prop.raw === null || // abscent
                value == null) // null or undefined
        ) {
            return true;
        }
        var options = prop.options;
        var type = options.type;
        var valid = !type;
        var expectedTypes = [];
        if (type) {
            if (!isArray(type)) {
                type = [type];
            }
            for (var i = 0; i < type.length && !valid; i++) {
                var assertedType = assertType(value, type[i]);
                expectedTypes.push(assertedType.expectedType);
                valid = assertedType.valid;
            }
        }
        if (!valid) {
            if ('development' !== 'production') {
                warn('Invalid prop: type check failed for prop "' + prop.name + '".' + ' Expected ' + expectedTypes.map(formatType).join(', ') + ', got ' + formatValue(value) + '.', vm);
            }
            return false;
        }
        var validator = options.validator;
        if (validator) {
            if (!validator(value)) {
                'development' !== 'production' && warn('Invalid prop: custom validator check failed for prop "' + prop.name + '".', vm);
                return false;
            }
        }
        return true;
    }

    /**
     * Force parsing value with coerce option.
     *
     * @param {*} value
     * @param {Object} options
     * @return {*}
     */

    function coerceProp(prop, value) {
        var coerce = prop.options.coerce;
        if (!coerce) {
            return value;
        }
        // coerce is a function
        return coerce(value);
    }

    /**
     * Assert the type of a value
     *
     * @param {*} value
     * @param {Function} type
     * @return {Object}
     */

    function assertType(value, type) {
        var valid;
        var expectedType;
        if (type === String) {
            expectedType = 'string';
            valid = typeof value === expectedType;
        } else if (type === Number) {
            expectedType = 'number';
            valid = typeof value === expectedType;
        } else if (type === Boolean) {
            expectedType = 'boolean';
            valid = typeof value === expectedType;
        } else if (type === Function) {
            expectedType = 'function';
            valid = typeof value === expectedType;
        } else if (type === Object) {
            expectedType = 'object';
            valid = isPlainObject(value);
        } else if (type === Array) {
            expectedType = 'array';
            valid = isArray(value);
        } else {
            valid = value instanceof type;
        }
        return {
            valid: valid,
            expectedType: expectedType
        };
    }

    /**
     * Format type for output
     *
     * @param {String} type
     * @return {String}
     */

    function formatType(type) {
        return type ? type.charAt(0).toUpperCase() + type.slice(1) : 'custom type';
    }

    /**
     * Format value
     *
     * @param {*} value
     * @return {String}
     */

    function formatValue(val) {
        return Object.prototype.toString.call(val).slice(8, -1);
    }

    var bindingModes = config._propBindingModes;

    var propDef = {

        bind: function bind() {
            var child = this.vm;
            var parent = child._context;
            // passed in from compiler directly
            var prop = this.descriptor.prop;
            var childKey = prop.path;
            var parentKey = prop.parentPath;
            var twoWay = prop.mode === bindingModes.TWO_WAY;

            var parentWatcher = this.parentWatcher = new Watcher(parent, parentKey, function(val) {
                updateProp(child, prop, val);
            }, {
                twoWay: twoWay,
                filters: prop.filters,
                // important: props need to be observed on the
                // v-for scope if present
                scope: this._scope
            });

            // set the child initial value.
            initProp(child, prop, parentWatcher.value);

            // setup two-way binding
            if (twoWay) {
                // important: defer the child watcher creation until
                // the created hook (after data observation)
                var self = this;
                child.$once('pre-hook:created', function() {
                    self.childWatcher = new Watcher(child, childKey, function(val) {
                        parentWatcher.set(val);
                    }, {
                        // ensure sync upward before parent sync down.
                        // this is necessary in cases e.g. the child
                        // mutates a prop array, then replaces it. (#1683)
                        sync: true
                    });
                });
            }
        },

        unbind: function unbind() {
            this.parentWatcher.teardown();
            if (this.childWatcher) {
                this.childWatcher.teardown();
            }
        }
    };

    var queue$1 = [];
    var queued = false;

    /**
     * Push a job into the queue.
     *
     * @param {Function} job
     */

    function pushJob(job) {
        queue$1.push(job);
        if (!queued) {
            queued = true;
            nextTick(flush);
        }
    }

    /**
     * Flush the queue, and do one forced reflow before
     * triggering transitions.
     */

    function flush() {
        // Force layout
        var f = document.documentElement.offsetHeight;
        for (var i = 0; i < queue$1.length; i++) {
            queue$1[i]();
        }
        queue$1 = [];
        queued = false;
        // dummy return, so js linters don't complain about
        // unused variable f
        return f;
    }

    var TYPE_TRANSITION = 'transition';
    var TYPE_ANIMATION = 'animation';
    var transDurationProp = transitionProp + 'Duration';
    var animDurationProp = animationProp + 'Duration';

    /**
     * If a just-entered element is applied the
     * leave class while its enter transition hasn't started yet,
     * and the transitioned property has the same value for both
     * enter/leave, then the leave transition will be skipped and
     * the transitionend event never fires. This function ensures
     * its callback to be called after a transition has started
     * by waiting for double raf.
     *
     * It falls back to setTimeout on devices that support CSS
     * transitions but not raf (e.g. Android 4.2 browser) - since
     * these environments are usually slow, we are giving it a
     * relatively large timeout.
     */

    var raf = inBrowser && window.requestAnimationFrame;
    var waitForTransitionStart = raf
        /* istanbul ignore next */
        ? function(fn) {
            raf(function() {
                raf(fn);
            });
        } : function(fn) {
            setTimeout(fn, 50);
        };

    /**
     * A Transition object that encapsulates the state and logic
     * of the transition.
     *
     * @param {Element} el
     * @param {String} id
     * @param {Object} hooks
     * @param {Vue} vm
     */
    function Transition(el, id, hooks, vm) {
        this.id = id;
        this.el = el;
        this.enterClass = hooks && hooks.enterClass || id + '-enter';
        this.leaveClass = hooks && hooks.leaveClass || id + '-leave';
        this.hooks = hooks;
        this.vm = vm;
        // async state
        this.pendingCssEvent = this.pendingCssCb = this.cancel = this.pendingJsCb = this.op = this.cb = null;
        this.justEntered = false;
        this.entered = this.left = false;
        this.typeCache = {};
        // check css transition type
        this.type = hooks && hooks.type;
        /* istanbul ignore if */
        if ('development' !== 'production') {
            if (this.type && this.type !== TYPE_TRANSITION && this.type !== TYPE_ANIMATION) {
                warn('invalid CSS transition type for transition="' + this.id + '": ' + this.type, vm);
            }
        }
        // bind
        var self = this;
        ['enterNextTick', 'enterDone', 'leaveNextTick', 'leaveDone'].forEach(function(m) {
            self[m] = bind(self[m], self);
        });
    }

    var p$1 = Transition.prototype;

    /**
     * Start an entering transition.
     *
     * 1. enter transition triggered
     * 2. call beforeEnter hook
     * 3. add enter class
     * 4. insert/show element
     * 5. call enter hook (with possible explicit js callback)
     * 6. reflow
     * 7. based on transition type:
     *    - transition:
     *        remove class now, wait for transitionend,
     *        then done if there's no explicit js callback.
     *    - animation:
     *        wait for animationend, remove class,
     *        then done if there's no explicit js callback.
     *    - no css transition:
     *        done now if there's no explicit js callback.
     * 8. wait for either done or js callback, then call
     *    afterEnter hook.
     *
     * @param {Function} op - insert/show the element
     * @param {Function} [cb]
     */

    p$1.enter = function(op, cb) {
        this.cancelPending();
        this.callHook('beforeEnter');
        this.cb = cb;
        addClass(this.el, this.enterClass);
        op();
        this.entered = false;
        this.callHookWithCb('enter');
        if (this.entered) {
            return; // user called done synchronously.
        }
        this.cancel = this.hooks && this.hooks.enterCancelled;
        pushJob(this.enterNextTick);
    };

    /**
     * The "nextTick" phase of an entering transition, which is
     * to be pushed into a queue and executed after a reflow so
     * that removing the class can trigger a CSS transition.
     */

    p$1.enterNextTick = function() {
        var _this = this;

        // prevent transition skipping
        this.justEntered = true;
        waitForTransitionStart(function() {
            _this.justEntered = false;
        });
        var enterDone = this.enterDone;
        var type = this.getCssTransitionType(this.enterClass);
        if (!this.pendingJsCb) {
            if (type === TYPE_TRANSITION) {
                // trigger transition by removing enter class now
                removeClass(this.el, this.enterClass);
                this.setupCssCb(transitionEndEvent, enterDone);
            } else if (type === TYPE_ANIMATION) {
                this.setupCssCb(animationEndEvent, enterDone);
            } else {
                enterDone();
            }
        } else if (type === TYPE_TRANSITION) {
            removeClass(this.el, this.enterClass);
        }
    };

    /**
     * The "cleanup" phase of an entering transition.
     */

    p$1.enterDone = function() {
        this.entered = true;
        this.cancel = this.pendingJsCb = null;
        removeClass(this.el, this.enterClass);
        this.callHook('afterEnter');
        if (this.cb) this.cb();
    };

    /**
     * Start a leaving transition.
     *
     * 1. leave transition triggered.
     * 2. call beforeLeave hook
     * 3. add leave class (trigger css transition)
     * 4. call leave hook (with possible explicit js callback)
     * 5. reflow if no explicit js callback is provided
     * 6. based on transition type:
     *    - transition or animation:
     *        wait for end event, remove class, then done if
     *        there's no explicit js callback.
     *    - no css transition:
     *        done if there's no explicit js callback.
     * 7. wait for either done or js callback, then call
     *    afterLeave hook.
     *
     * @param {Function} op - remove/hide the element
     * @param {Function} [cb]
     */

    p$1.leave = function(op, cb) {
        this.cancelPending();
        this.callHook('beforeLeave');
        this.op = op;
        this.cb = cb;
        addClass(this.el, this.leaveClass);
        this.left = false;
        this.callHookWithCb('leave');
        if (this.left) {
            return; // user called done synchronously.
        }
        this.cancel = this.hooks && this.hooks.leaveCancelled;
        // only need to handle leaveDone if
        // 1. the transition is already done (synchronously called
        //    by the user, which causes this.op set to null)
        // 2. there's no explicit js callback
        if (this.op && !this.pendingJsCb) {
            // if a CSS transition leaves immediately after enter,
            // the transitionend event never fires. therefore we
            // detect such cases and end the leave immediately.
            if (this.justEntered) {
                this.leaveDone();
            } else {
                pushJob(this.leaveNextTick);
            }
        }
    };

    /**
     * The "nextTick" phase of a leaving transition.
     */

    p$1.leaveNextTick = function() {
        var type = this.getCssTransitionType(this.leaveClass);
        if (type) {
            var event = type === TYPE_TRANSITION ? transitionEndEvent : animationEndEvent;
            this.setupCssCb(event, this.leaveDone);
        } else {
            this.leaveDone();
        }
    };

    /**
     * The "cleanup" phase of a leaving transition.
     */

    p$1.leaveDone = function() {
        this.left = true;
        this.cancel = this.pendingJsCb = null;
        this.op();
        removeClass(this.el, this.leaveClass);
        this.callHook('afterLeave');
        if (this.cb) this.cb();
        this.op = null;
    };

    /**
     * Cancel any pending callbacks from a previously running
     * but not finished transition.
     */

    p$1.cancelPending = function() {
        this.op = this.cb = null;
        var hasPending = false;
        if (this.pendingCssCb) {
            hasPending = true;
            off(this.el, this.pendingCssEvent, this.pendingCssCb);
            this.pendingCssEvent = this.pendingCssCb = null;
        }
        if (this.pendingJsCb) {
            hasPending = true;
            this.pendingJsCb.cancel();
            this.pendingJsCb = null;
        }
        if (hasPending) {
            removeClass(this.el, this.enterClass);
            removeClass(this.el, this.leaveClass);
        }
        if (this.cancel) {
            this.cancel.call(this.vm, this.el);
            this.cancel = null;
        }
    };

    /**
     * Call a user-provided synchronous hook function.
     *
     * @param {String} type
     */

    p$1.callHook = function(type) {
        if (this.hooks && this.hooks[type]) {
            this.hooks[type].call(this.vm, this.el);
        }
    };

    /**
     * Call a user-provided, potentially-async hook function.
     * We check for the length of arguments to see if the hook
     * expects a `done` callback. If true, the transition's end
     * will be determined by when the user calls that callback;
     * otherwise, the end is determined by the CSS transition or
     * animation.
     *
     * @param {String} type
     */

    p$1.callHookWithCb = function(type) {
        var hook = this.hooks && this.hooks[type];
        if (hook) {
            if (hook.length > 1) {
                this.pendingJsCb = cancellable(this[type + 'Done']);
            }
            hook.call(this.vm, this.el, this.pendingJsCb);
        }
    };

    /**
     * Get an element's transition type based on the
     * calculated styles.
     *
     * @param {String} className
     * @return {Number}
     */

    p$1.getCssTransitionType = function(className) {
        /* istanbul ignore if */
        if (!transitionEndEvent ||
            // skip CSS transitions if page is not visible -
            // this solves the issue of transitionend events not
            // firing until the page is visible again.
            // pageVisibility API is supported in IE10+, same as
            // CSS transitions.
            document.hidden ||
            // explicit js-only transition
            this.hooks && this.hooks.css === false ||
            // element is hidden
            isHidden(this.el)) {
            return;
        }
        var type = this.type || this.typeCache[className];
        if (type) return type;
        var inlineStyles = this.el.style;
        var computedStyles = window.getComputedStyle(this.el);
        var transDuration = inlineStyles[transDurationProp] || computedStyles[transDurationProp];
        if (transDuration && transDuration !== '0s') {
            type = TYPE_TRANSITION;
        } else {
            var animDuration = inlineStyles[animDurationProp] || computedStyles[animDurationProp];
            if (animDuration && animDuration !== '0s') {
                type = TYPE_ANIMATION;
            }
        }
        if (type) {
            this.typeCache[className] = type;
        }
        return type;
    };

    /**
     * Setup a CSS transitionend/animationend callback.
     *
     * @param {String} event
     * @param {Function} cb
     */

    p$1.setupCssCb = function(event, cb) {
        this.pendingCssEvent = event;
        var self = this;
        var el = this.el;
        var onEnd = this.pendingCssCb = function(e) {
            if (e.target === el) {
                off(el, event, onEnd);
                self.pendingCssEvent = self.pendingCssCb = null;
                if (!self.pendingJsCb && cb) {
                    cb();
                }
            }
        };
        on(el, event, onEnd);
    };

    /**
     * Check if an element is hidden - in that case we can just
     * skip the transition alltogether.
     *
     * @param {Element} el
     * @return {Boolean}
     */

    function isHidden(el) {
        if (/svg$/.test(el.namespaceURI)) {
            // SVG elements do not have offset(Width|Height)
            // so we need to check the client rect
            var rect = el.getBoundingClientRect();
            return !(rect.width || rect.height);
        } else {
            return !(el.offsetWidth || el.offsetHeight || el.getClientRects().length);
        }
    }

    var transition$1 = {

        priority: TRANSITION,

        update: function update(id, oldId) {
            var el = this.el;
            // resolve on owner vm
            var hooks = resolveAsset(this.vm.$options, 'transitions', id);
            id = id || 'v';
            el.__v_trans = new Transition(el, id, hooks, this.vm);
            if (oldId) {
                removeClass(el, oldId + '-transition');
            }
            addClass(el, id + '-transition');
        }
    };

    var internalDirectives = {
        style: style,
        'class': vClass,
        component: component,
        prop: propDef,
        transition: transition$1
    };

    // special binding prefixes
    var bindRE = /^v-bind:|^:/;
    var onRE = /^v-on:|^@/;
    var dirAttrRE = /^v-([^:]+)(?:$|:(.*)$)/;
    var modifierRE = /\.[^\.]+/g;
    var transitionRE = /^(v-bind:|:)?transition$/;

    // default directive priority
    var DEFAULT_PRIORITY = 1000;
    var DEFAULT_TERMINAL_PRIORITY = 2000;

    /**
     * Compile a template and return a reusable composite link
     * function, which recursively contains more link functions
     * inside. This top level compile function would normally
     * be called on instance root nodes, but can also be used
     * for partial compilation if the partial argument is true.
     *
     * The returned composite link function, when called, will
     * return an unlink function that tearsdown all directives
     * created during the linking phase.
     *
     * @param {Element|DocumentFragment} el
     * @param {Object} options
     * @param {Boolean} partial
     * @return {Function}
     */

    function compile(el, options, partial) {
        // link function for the node itself.
        var nodeLinkFn = partial || !options._asComponent ? compileNode(el, options) : null;
        // link function for the childNodes
        var childLinkFn = !(nodeLinkFn && nodeLinkFn.terminal) && !isScript(el) && el.hasChildNodes() ? compileNodeList(el.childNodes, options) : null;

        /**
         * A composite linker function to be called on a already
         * compiled piece of DOM, which instantiates all directive
         * instances.
         *
         * @param {Vue} vm
         * @param {Element|DocumentFragment} el
         * @param {Vue} [host] - host vm of transcluded content
         * @param {Object} [scope] - v-for scope
         * @param {Fragment} [frag] - link context fragment
         * @return {Function|undefined}
         */

        return function compositeLinkFn(vm, el, host, scope, frag) {
            // cache childNodes before linking parent, fix #657
            var childNodes = toArray(el.childNodes);
            // link
            var dirs = linkAndCapture(function compositeLinkCapturer() {
                if (nodeLinkFn) nodeLinkFn(vm, el, host, scope, frag);
                if (childLinkFn) childLinkFn(vm, childNodes, host, scope, frag);
            }, vm);
            return makeUnlinkFn(vm, dirs);
        };
    }

    /**
     * Apply a linker to a vm/element pair and capture the
     * directives created during the process.
     *
     * @param {Function} linker
     * @param {Vue} vm
     */

    function linkAndCapture(linker, vm) {
        /* istanbul ignore if */
        if ('development' === 'production') {}
        var originalDirCount = vm._directives.length;
        linker();
        var dirs = vm._directives.slice(originalDirCount);
        dirs.sort(directiveComparator);
        for (var i = 0, l = dirs.length; i < l; i++) {
            dirs[i]._bind();
        }
        return dirs;
    }

    /**
     * Directive priority sort comparator
     *
     * @param {Object} a
     * @param {Object} b
     */

    function directiveComparator(a, b) {
        a = a.descriptor.def.priority || DEFAULT_PRIORITY;
        b = b.descriptor.def.priority || DEFAULT_PRIORITY;
        return a > b ? -1 : a === b ? 0 : 1;
    }

    /**
     * Linker functions return an unlink function that
     * tearsdown all directives instances generated during
     * the process.
     *
     * We create unlink functions with only the necessary
     * information to avoid retaining additional closures.
     *
     * @param {Vue} vm
     * @param {Array} dirs
     * @param {Vue} [context]
     * @param {Array} [contextDirs]
     * @return {Function}
     */

    function makeUnlinkFn(vm, dirs, context, contextDirs) {
        function unlink(destroying) {
            teardownDirs(vm, dirs, destroying);
            if (context && contextDirs) {
                teardownDirs(context, contextDirs);
            }
        }
        // expose linked directives
        unlink.dirs = dirs;
        return unlink;
    }

    /**
     * Teardown partial linked directives.
     *
     * @param {Vue} vm
     * @param {Array} dirs
     * @param {Boolean} destroying
     */

    function teardownDirs(vm, dirs, destroying) {
        var i = dirs.length;
        while (i--) {
            dirs[i]._teardown();
            if ('development' !== 'production' && !destroying) {
                vm._directives.$remove(dirs[i]);
            }
        }
    }

    /**
     * Compile link props on an instance.
     *
     * @param {Vue} vm
     * @param {Element} el
     * @param {Object} props
     * @param {Object} [scope]
     * @return {Function}
     */

    function compileAndLinkProps(vm, el, props, scope) {
        var propsLinkFn = compileProps(el, props, vm);
        var propDirs = linkAndCapture(function() {
            propsLinkFn(vm, scope);
        }, vm);
        return makeUnlinkFn(vm, propDirs);
    }

    /**
     * Compile the root element of an instance.
     *
     * 1. attrs on context container (context scope)
     * 2. attrs on the component template root node, if
     *    replace:true (child scope)
     *
     * If this is a fragment instance, we only need to compile 1.
     *
     * @param {Element} el
     * @param {Object} options
     * @param {Object} contextOptions
     * @return {Function}
     */

    function compileRoot(el, options, contextOptions) {
        var containerAttrs = options._containerAttrs;
        var replacerAttrs = options._replacerAttrs;
        var contextLinkFn, replacerLinkFn;

        // only need to compile other attributes for
        // non-fragment instances
        if (el.nodeType !== 11) {
            // for components, container and replacer need to be
            // compiled separately and linked in different scopes.
            if (options._asComponent) {
                // 2. container attributes
                if (containerAttrs && contextOptions) {
                    contextLinkFn = compileDirectives(containerAttrs, contextOptions);
                }
                if (replacerAttrs) {
                    // 3. replacer attributes
                    replacerLinkFn = compileDirectives(replacerAttrs, options);
                }
            } else {
                // non-component, just compile as a normal element.
                replacerLinkFn = compileDirectives(el.attributes, options);
            }
        } else if ('development' !== 'production' && containerAttrs) {
            // warn container directives for fragment instances
            var names = containerAttrs.filter(function(attr) {
                // allow vue-loader/vueify scoped css attributes
                return attr.name.indexOf('_v-') < 0 &&
                    // allow event listeners
                    !onRE.test(attr.name) &&
                    // allow slots
                    attr.name !== 'slot';
            }).map(function(attr) {
                return '"' + attr.name + '"';
            });
            if (names.length) {
                var plural = names.length > 1;
                warn('Attribute' + (plural ? 's ' : ' ') + names.join(', ') + (plural ? ' are' : ' is') + ' ignored on component ' + '<' + options.el.tagName.toLowerCase() + '> because ' + 'the component is a fragment instance: ' + 'http://vuejs.org/guide/components.html#Fragment-Instance');
            }
        }

        options._containerAttrs = options._replacerAttrs = null;
        return function rootLinkFn(vm, el, scope) {
            // link context scope dirs
            var context = vm._context;
            var contextDirs;
            if (context && contextLinkFn) {
                contextDirs = linkAndCapture(function() {
                    contextLinkFn(context, el, null, scope);
                }, context);
            }

            // link self
            var selfDirs = linkAndCapture(function() {
                if (replacerLinkFn) replacerLinkFn(vm, el);
            }, vm);

            // return the unlink function that tearsdown context
            // container directives.
            return makeUnlinkFn(vm, selfDirs, context, contextDirs);
        };
    }

    /**
     * Compile a node and return a nodeLinkFn based on the
     * node type.
     *
     * @param {Node} node
     * @param {Object} options
     * @return {Function|null}
     */

    function compileNode(node, options) {
        var type = node.nodeType;
        if (type === 1 && !isScript(node)) {
            return compileElement(node, options);
        } else if (type === 3 && node.data.trim()) {
            return compileTextNode(node, options);
        } else {
            return null;
        }
    }

    /**
     * Compile an element and return a nodeLinkFn.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Function|null}
     */

    function compileElement(el, options) {
        // preprocess textareas.
        // textarea treats its text content as the initial value.
        // just bind it as an attr directive for value.
        if (el.tagName === 'TEXTAREA') {
            var tokens = parseText(el.value);
            if (tokens) {
                el.setAttribute(':value', tokensToExp(tokens));
                el.value = '';
            }
        }
        var linkFn;
        var hasAttrs = el.hasAttributes();
        var attrs = hasAttrs && toArray(el.attributes);
        // check terminal directives (for & if)
        if (hasAttrs) {
            linkFn = checkTerminalDirectives(el, attrs, options);
        }
        // check element directives
        if (!linkFn) {
            linkFn = checkElementDirectives(el, options);
        }
        // check component
        if (!linkFn) {
            linkFn = checkComponent(el, options);
        }
        // normal directives
        if (!linkFn && hasAttrs) {
            linkFn = compileDirectives(attrs, options);
        }
        return linkFn;
    }

    /**
     * Compile a textNode and return a nodeLinkFn.
     *
     * @param {TextNode} node
     * @param {Object} options
     * @return {Function|null} textNodeLinkFn
     */

    function compileTextNode(node, options) {
        // skip marked text nodes
        if (node._skip) {
            return removeText;
        }

        var tokens = parseText(node.wholeText);
        if (!tokens) {
            return null;
        }

        // mark adjacent text nodes as skipped,
        // because we are using node.wholeText to compile
        // all adjacent text nodes together. This fixes
        // issues in IE where sometimes it splits up a single
        // text node into multiple ones.
        var next = node.nextSibling;
        while (next && next.nodeType === 3) {
            next._skip = true;
            next = next.nextSibling;
        }

        var frag = document.createDocumentFragment();
        var el, token;
        for (var i = 0, l = tokens.length; i < l; i++) {
            token = tokens[i];
            el = token.tag ? processTextToken(token, options) : document.createTextNode(token.value);
            frag.appendChild(el);
        }
        return makeTextNodeLinkFn(tokens, frag, options);
    }

    /**
     * Linker for an skipped text node.
     *
     * @param {Vue} vm
     * @param {Text} node
     */

    function removeText(vm, node) {
        remove(node);
    }

    /**
     * Process a single text token.
     *
     * @param {Object} token
     * @param {Object} options
     * @return {Node}
     */

    function processTextToken(token, options) {
        var el;
        if (token.oneTime) {
            el = document.createTextNode(token.value);
        } else {
            if (token.html) {
                el = document.createComment('v-html');
                setTokenType('html');
            } else {
                // IE will clean up empty textNodes during
                // frag.cloneNode(true), so we have to give it
                // something here...
                el = document.createTextNode(' ');
                setTokenType('text');
            }
        }

        function setTokenType(type) {
            if (token.descriptor) return;
            var parsed = parseDirective(token.value);
            token.descriptor = {
                name: type,
                def: directives[type],
                expression: parsed.expression,
                filters: parsed.filters
            };
        }
        return el;
    }

    /**
     * Build a function that processes a textNode.
     *
     * @param {Array<Object>} tokens
     * @param {DocumentFragment} frag
     */

    function makeTextNodeLinkFn(tokens, frag) {
        return function textNodeLinkFn(vm, el, host, scope) {
            var fragClone = frag.cloneNode(true);
            var childNodes = toArray(fragClone.childNodes);
            var token, value, node;
            for (var i = 0, l = tokens.length; i < l; i++) {
                token = tokens[i];
                value = token.value;
                if (token.tag) {
                    node = childNodes[i];
                    if (token.oneTime) {
                        value = (scope || vm).$eval(value);
                        if (token.html) {
                            replace(node, parseTemplate(value, true));
                        } else {
                            node.data = value;
                        }
                    } else {
                        vm._bindDir(token.descriptor, node, host, scope);
                    }
                }
            }
            replace(el, fragClone);
        };
    }

    /**
     * Compile a node list and return a childLinkFn.
     *
     * @param {NodeList} nodeList
     * @param {Object} options
     * @return {Function|undefined}
     */

    function compileNodeList(nodeList, options) {
        var linkFns = [];
        var nodeLinkFn, childLinkFn, node;
        for (var i = 0, l = nodeList.length; i < l; i++) {
            node = nodeList[i];
            nodeLinkFn = compileNode(node, options);
            childLinkFn = !(nodeLinkFn && nodeLinkFn.terminal) && node.tagName !== 'SCRIPT' && node.hasChildNodes() ? compileNodeList(node.childNodes, options) : null;
            linkFns.push(nodeLinkFn, childLinkFn);
        }
        return linkFns.length ? makeChildLinkFn(linkFns) : null;
    }

    /**
     * Make a child link function for a node's childNodes.
     *
     * @param {Array<Function>} linkFns
     * @return {Function} childLinkFn
     */

    function makeChildLinkFn(linkFns) {
        return function childLinkFn(vm, nodes, host, scope, frag) {
            var node, nodeLinkFn, childrenLinkFn;
            for (var i = 0, n = 0, l = linkFns.length; i < l; n++) {
                node = nodes[n];
                nodeLinkFn = linkFns[i++];
                childrenLinkFn = linkFns[i++];
                // cache childNodes before linking parent, fix #657
                var childNodes = toArray(node.childNodes);
                if (nodeLinkFn) {
                    nodeLinkFn(vm, node, host, scope, frag);
                }
                if (childrenLinkFn) {
                    childrenLinkFn(vm, childNodes, host, scope, frag);
                }
            }
        };
    }

    /**
     * Check for element directives (custom elements that should
     * be resovled as terminal directives).
     *
     * @param {Element} el
     * @param {Object} options
     */

    function checkElementDirectives(el, options) {
        var tag = el.tagName.toLowerCase();
        if (commonTagRE.test(tag)) {
            return;
        }
        var def = resolveAsset(options, 'elementDirectives', tag);
        if (def) {
            return makeTerminalNodeLinkFn(el, tag, '', options, def);
        }
    }

    /**
     * Check if an element is a component. If yes, return
     * a component link function.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Function|undefined}
     */

    function checkComponent(el, options) {
        var component = checkComponentAttr(el, options);
        if (component) {
            var ref = findRef(el);
            var descriptor = {
                name: 'component',
                ref: ref,
                expression: component.id,
                def: internalDirectives.component,
                modifiers: {
                    literal: !component.dynamic
                }
            };
            var componentLinkFn = function componentLinkFn(vm, el, host, scope, frag) {
                if (ref) {
                    defineReactive((scope || vm).$refs, ref, null);
                }
                vm._bindDir(descriptor, el, host, scope, frag);
            };
            componentLinkFn.terminal = true;
            return componentLinkFn;
        }
    }

    /**
     * Check an element for terminal directives in fixed order.
     * If it finds one, return a terminal link function.
     *
     * @param {Element} el
     * @param {Array} attrs
     * @param {Object} options
     * @return {Function} terminalLinkFn
     */

    function checkTerminalDirectives(el, attrs, options) {
        // skip v-pre
        if (getAttr(el, 'v-pre') !== null) {
            return skip;
        }
        // skip v-else block, but only if following v-if
        if (el.hasAttribute('v-else')) {
            var prev = el.previousElementSibling;
            if (prev && prev.hasAttribute('v-if')) {
                return skip;
            }
        }

        var attr, name, value, modifiers, matched, dirName, rawName, arg, def, termDef;
        for (var i = 0, j = attrs.length; i < j; i++) {
            attr = attrs[i];
            name = attr.name.replace(modifierRE, '');
            if (matched = name.match(dirAttrRE)) {
                def = resolveAsset(options, 'directives', matched[1]);
                if (def && def.terminal) {
                    if (!termDef || (def.priority || DEFAULT_TERMINAL_PRIORITY) > termDef.priority) {
                        termDef = def;
                        rawName = attr.name;
                        modifiers = parseModifiers(attr.name);
                        value = attr.value;
                        dirName = matched[1];
                        arg = matched[2];
                    }
                }
            }
        }

        if (termDef) {
            return makeTerminalNodeLinkFn(el, dirName, value, options, termDef, rawName, arg, modifiers);
        }
    }

    function skip() {}
    skip.terminal = true;

    /**
     * Build a node link function for a terminal directive.
     * A terminal link function terminates the current
     * compilation recursion and handles compilation of the
     * subtree in the directive.
     *
     * @param {Element} el
     * @param {String} dirName
     * @param {String} value
     * @param {Object} options
     * @param {Object} def
     * @param {String} [rawName]
     * @param {String} [arg]
     * @param {Object} [modifiers]
     * @return {Function} terminalLinkFn
     */

    function makeTerminalNodeLinkFn(el, dirName, value, options, def, rawName, arg, modifiers) {
        var parsed = parseDirective(value);
        var descriptor = {
            name: dirName,
            arg: arg,
            expression: parsed.expression,
            filters: parsed.filters,
            raw: value,
            attr: rawName,
            modifiers: modifiers,
            def: def
        };
        // check ref for v-for and router-view
        if (dirName === 'for' || dirName === 'router-view') {
            descriptor.ref = findRef(el);
        }
        var fn = function terminalNodeLinkFn(vm, el, host, scope, frag) {
            if (descriptor.ref) {
                defineReactive((scope || vm).$refs, descriptor.ref, null);
            }
            vm._bindDir(descriptor, el, host, scope, frag);
        };
        fn.terminal = true;
        return fn;
    }

    /**
     * Compile the directives on an element and return a linker.
     *
     * @param {Array|NamedNodeMap} attrs
     * @param {Object} options
     * @return {Function}
     */

    function compileDirectives(attrs, options) {
        var i = attrs.length;
        var dirs = [];
        var attr, name, value, rawName, rawValue, dirName, arg, modifiers, dirDef, tokens, matched;
        while (i--) {
            attr = attrs[i];
            name = rawName = attr.name;
            value = rawValue = attr.value;
            tokens = parseText(value);
            // reset arg
            arg = null;
            // check modifiers
            modifiers = parseModifiers(name);
            name = name.replace(modifierRE, '');

            // attribute interpolations
            if (tokens) {
                value = tokensToExp(tokens);
                arg = name;
                pushDir('bind', directives.bind, tokens);
                // warn against mixing mustaches with v-bind
                if ('development' !== 'production') {
                    if (name === 'class' && Array.prototype.some.call(attrs, function(attr) {
                            return attr.name === ':class' || attr.name === 'v-bind:class';
                        })) {
                        warn('class="' + rawValue + '": Do not mix mustache interpolation ' + 'and v-bind for "class" on the same element. Use one or the other.', options);
                    }
                }
            } else

            // special attribute: transition
            if (transitionRE.test(name)) {
                modifiers.literal = !bindRE.test(name);
                pushDir('transition', internalDirectives.transition);
            } else

            // event handlers
            if (onRE.test(name)) {
                arg = name.replace(onRE, '');
                pushDir('on', directives.on);
            } else

            // attribute bindings
            if (bindRE.test(name)) {
                dirName = name.replace(bindRE, '');
                if (dirName === 'style' || dirName === 'class') {
                    pushDir(dirName, internalDirectives[dirName]);
                } else {
                    arg = dirName;
                    pushDir('bind', directives.bind);
                }
            } else

            // normal directives
            if (matched = name.match(dirAttrRE)) {
                dirName = matched[1];
                arg = matched[2];

                // skip v-else (when used with v-show)
                if (dirName === 'else') {
                    continue;
                }

                dirDef = resolveAsset(options, 'directives', dirName, true);
                if (dirDef) {
                    pushDir(dirName, dirDef);
                }
            }
        }

        /**
         * Push a directive.
         *
         * @param {String} dirName
         * @param {Object|Function} def
         * @param {Array} [interpTokens]
         */

        function pushDir(dirName, def, interpTokens) {
            var hasOneTimeToken = interpTokens && hasOneTime(interpTokens);
            var parsed = !hasOneTimeToken && parseDirective(value);
            dirs.push({
                name: dirName,
                attr: rawName,
                raw: rawValue,
                def: def,
                arg: arg,
                modifiers: modifiers,
                // conversion from interpolation strings with one-time token
                // to expression is differed until directive bind time so that we
                // have access to the actual vm context for one-time bindings.
                expression: parsed && parsed.expression,
                filters: parsed && parsed.filters,
                interp: interpTokens,
                hasOneTime: hasOneTimeToken
            });
        }

        if (dirs.length) {
            return makeNodeLinkFn(dirs);
        }
    }

    /**
     * Parse modifiers from directive attribute name.
     *
     * @param {String} name
     * @return {Object}
     */

    function parseModifiers(name) {
        var res = Object.create(null);
        var match = name.match(modifierRE);
        if (match) {
            var i = match.length;
            while (i--) {
                res[match[i].slice(1)] = true;
            }
        }
        return res;
    }

    /**
     * Build a link function for all directives on a single node.
     *
     * @param {Array} directives
     * @return {Function} directivesLinkFn
     */

    function makeNodeLinkFn(directives) {
        return function nodeLinkFn(vm, el, host, scope, frag) {
            // reverse apply because it's sorted low to high
            var i = directives.length;
            while (i--) {
                vm._bindDir(directives[i], el, host, scope, frag);
            }
        };
    }

    /**
     * Check if an interpolation string contains one-time tokens.
     *
     * @param {Array} tokens
     * @return {Boolean}
     */

    function hasOneTime(tokens) {
        var i = tokens.length;
        while (i--) {
            if (tokens[i].oneTime) return true;
        }
    }

    function isScript(el) {
        return el.tagName === 'SCRIPT' && (!el.hasAttribute('type') || el.getAttribute('type') === 'text/javascript');
    }

    var specialCharRE = /[^\w\-:\.]/;

    /**
     * Process an element or a DocumentFragment based on a
     * instance option object. This allows us to transclude
     * a template node/fragment before the instance is created,
     * so the processed fragment can then be cloned and reused
     * in v-for.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Element|DocumentFragment}
     */

    function transclude(el, options) {
        // extract container attributes to pass them down
        // to compiler, because they need to be compiled in
        // parent scope. we are mutating the options object here
        // assuming the same object will be used for compile
        // right after this.
        if (options) {
            options._containerAttrs = extractAttrs(el);
        }
        // for template tags, what we want is its content as
        // a documentFragment (for fragment instances)
        if (isTemplate(el)) {
            el = parseTemplate(el);
        }
        if (options) {
            if (options._asComponent && !options.template) {
                options.template = '<slot></slot>';
            }
            if (options.template) {
                options._content = extractContent(el);
                el = transcludeTemplate(el, options);
            }
        }
        if (isFragment(el)) {
            // anchors for fragment instance
            // passing in `persist: true` to avoid them being
            // discarded by IE during template cloning
            prepend(createAnchor('v-start', true), el);
            el.appendChild(createAnchor('v-end', true));
        }
        return el;
    }

    /**
     * Process the template option.
     * If the replace option is true this will swap the $el.
     *
     * @param {Element} el
     * @param {Object} options
     * @return {Element|DocumentFragment}
     */

    function transcludeTemplate(el, options) {
        var template = options.template;
        var frag = parseTemplate(template, true);
        if (frag) {
            var replacer = frag.firstChild;
            var tag = replacer.tagName && replacer.tagName.toLowerCase();
            if (options.replace) {
                /* istanbul ignore if */
                if (el === document.body) {
                    'development' !== 'production' && warn('You are mounting an instance with a template to ' + '<body>. This will replace <body> entirely. You ' + 'should probably use `replace: false` here.');
                }
                // there are many cases where the instance must
                // become a fragment instance: basically anything that
                // can create more than 1 root nodes.
                if (
                    // multi-children template
                    frag.childNodes.length > 1 ||
                    // non-element template
                    replacer.nodeType !== 1 ||
                    // single nested component
                    tag === 'component' || resolveAsset(options, 'components', tag) || hasBindAttr(replacer, 'is') ||
                    // element directive
                    resolveAsset(options, 'elementDirectives', tag) ||
                    // for block
                    replacer.hasAttribute('v-for') ||
                    // if block
                    replacer.hasAttribute('v-if')) {
                    return frag;
                } else {
                    options._replacerAttrs = extractAttrs(replacer);
                    mergeAttrs(el, replacer);
                    return replacer;
                }
            } else {
                el.appendChild(frag);
                return el;
            }
        } else {
            'development' !== 'production' && warn('Invalid template option: ' + template);
        }
    }

    /**
     * Helper to extract a component container's attributes
     * into a plain object array.
     *
     * @param {Element} el
     * @return {Array}
     */

    function extractAttrs(el) {
        if (el.nodeType === 1 && el.hasAttributes()) {
            return toArray(el.attributes);
        }
    }

    /**
     * Merge the attributes of two elements, and make sure
     * the class names are merged properly.
     *
     * @param {Element} from
     * @param {Element} to
     */

    function mergeAttrs(from, to) {
        var attrs = from.attributes;
        var i = attrs.length;
        var name, value;
        while (i--) {
            name = attrs[i].name;
            value = attrs[i].value;
            if (!to.hasAttribute(name) && !specialCharRE.test(name)) {
                to.setAttribute(name, value);
            } else if (name === 'class' && !parseText(value) && (value = value.trim())) {
                value.split(/\s+/).forEach(function(cls) {
                    addClass(to, cls);
                });
            }
        }
    }

    /**
     * Scan and determine slot content distribution.
     * We do this during transclusion instead at compile time so that
     * the distribution is decoupled from the compilation order of
     * the slots.
     *
     * @param {Element|DocumentFragment} template
     * @param {Element} content
     * @param {Vue} vm
     */

    function resolveSlots(vm, content) {
        if (!content) {
            return;
        }
        var contents = vm._slotContents = Object.create(null);
        var el, name;
        for (var i = 0, l = content.children.length; i < l; i++) {
            el = content.children[i];
            /* eslint-disable no-cond-assign */
            if (name = el.getAttribute('slot')) {
                (contents[name] || (contents[name] = [])).push(el);
            }
            /* eslint-enable no-cond-assign */
            if ('development' !== 'production' && getBindAttr(el, 'slot')) {
                warn('The "slot" attribute must be static.', vm.$parent);
            }
        }
        for (name in contents) {
            contents[name] = extractFragment(contents[name], content);
        }
        if (content.hasChildNodes()) {
            var nodes = content.childNodes;
            if (nodes.length === 1 && nodes[0].nodeType === 3 && !nodes[0].data.trim()) {
                return;
            }
            contents['default'] = extractFragment(content.childNodes, content);
        }
    }

    /**
     * Extract qualified content nodes from a node list.
     *
     * @param {NodeList} nodes
     * @return {DocumentFragment}
     */

    function extractFragment(nodes, parent) {
        var frag = document.createDocumentFragment();
        nodes = toArray(nodes);
        for (var i = 0, l = nodes.length; i < l; i++) {
            var node = nodes[i];
            if (isTemplate(node) && !node.hasAttribute('v-if') && !node.hasAttribute('v-for')) {
                parent.removeChild(node);
                node = parseTemplate(node, true);
            }
            frag.appendChild(node);
        }
        return frag;
    }



    var compiler = Object.freeze({
        compile: compile,
        compileAndLinkProps: compileAndLinkProps,
        compileRoot: compileRoot,
        transclude: transclude,
        resolveSlots: resolveSlots
    });

    function stateMixin(Vue) {
        /**
         * Accessor for `$data` property, since setting $data
         * requires observing the new object and updating
         * proxied properties.
         */

        Object.defineProperty(Vue.prototype, '$data', {
            get: function get() {
                return this._data;
            },
            set: function set(newData) {
                if (newData !== this._data) {
                    this._setData(newData);
                }
            }
        });

        /**
         * Setup the scope of an instance, which contains:
         * - observed data
         * - computed properties
         * - user methods
         * - meta properties
         */

        Vue.prototype._initState = function() {
            this._initProps();
            this._initMeta();
            this._initMethods();
            this._initData();
            this._initComputed();
        };

        /**
         * Initialize props.
         */

        Vue.prototype._initProps = function() {
            var options = this.$options;
            var el = options.el;
            var props = options.props;
            if (props && !el) {
                'development' !== 'production' && warn('Props will not be compiled if no `el` option is ' + 'provided at instantiation.', this);
            }
            // make sure to convert string selectors into element now
            el = options.el = query(el);
            this._propsUnlinkFn = el && el.nodeType === 1 && props
                // props must be linked in proper scope if inside v-for
                ? compileAndLinkProps(this, el, props, this._scope) : null;
        };

        /**
         * Initialize the data.
         */

        Vue.prototype._initData = function() {
            var dataFn = this.$options.data;
            var data = this._data = dataFn ? dataFn() : {};
            if (!isPlainObject(data)) {
                data = {};
                'development' !== 'production' && warn('data functions should return an object.', this);
            }
            var props = this._props;
            // proxy data on instance
            var keys = Object.keys(data);
            var i, key;
            i = keys.length;
            while (i--) {
                key = keys[i];
                // there are two scenarios where we can proxy a data key:
                // 1. it's not already defined as a prop
                // 2. it's provided via a instantiation option AND there are no
                //    template prop present
                if (!props || !hasOwn(props, key)) {
                    this._proxy(key);
                } else if ('development' !== 'production') {
                    warn('Data field "' + key + '" is already defined ' + 'as a prop. To provide default value for a prop, use the "default" ' + 'prop option; if you want to pass prop values to an instantiation ' + 'call, use the "propsData" option.', this);
                }
            }
            // observe data
            observe(data, this);
        };

        /**
         * Swap the instance's $data. Called in $data's setter.
         *
         * @param {Object} newData
         */

        Vue.prototype._setData = function(newData) {
            newData = newData || {};
            var oldData = this._data;
            this._data = newData;
            var keys, key, i;
            // unproxy keys not present in new data
            keys = Object.keys(oldData);
            i = keys.length;
            while (i--) {
                key = keys[i];
                if (!(key in newData)) {
                    this._unproxy(key);
                }
            }
            // proxy keys not already proxied,
            // and trigger change for changed values
            keys = Object.keys(newData);
            i = keys.length;
            while (i--) {
                key = keys[i];
                if (!hasOwn(this, key)) {
                    // new property
                    this._proxy(key);
                }
            }
            oldData.__ob__.removeVm(this);
            observe(newData, this);
            this._digest();
        };

        /**
         * Proxy a property, so that
         * vm.prop === vm._data.prop
         *
         * @param {String} key
         */

        Vue.prototype._proxy = function(key) {
            if (!isReserved(key)) {
                // need to store ref to self here
                // because these getter/setters might
                // be called by child scopes via
                // prototype inheritance.
                var self = this;
                Object.defineProperty(self, key, {
                    configurable: true,
                    enumerable: true,
                    get: function proxyGetter() {
                        return self._data[key];
                    },
                    set: function proxySetter(val) {
                        self._data[key] = val;
                    }
                });
            }
        };

        /**
         * Unproxy a property.
         *
         * @param {String} key
         */

        Vue.prototype._unproxy = function(key) {
            if (!isReserved(key)) {
                delete this[key];
            }
        };

        /**
         * Force update on every watcher in scope.
         */

        Vue.prototype._digest = function() {
            for (var i = 0, l = this._watchers.length; i < l; i++) {
                this._watchers[i].update(true); // shallow updates
            }
        };

        /**
         * Setup computed properties. They are essentially
         * special getter/setters
         */

        function noop() {}
        Vue.prototype._initComputed = function() {
            var computed = this.$options.computed;
            if (computed) {
                for (var key in computed) {
                    var userDef = computed[key];
                    var def = {
                        enumerable: true,
                        configurable: true
                    };
                    if (typeof userDef === 'function') {
                        def.get = makeComputedGetter(userDef, this);
                        def.set = noop;
                    } else {
                        def.get = userDef.get ? userDef.cache !== false ? makeComputedGetter(userDef.get, this) : bind(userDef.get, this) : noop;
                        def.set = userDef.set ? bind(userDef.set, this) : noop;
                    }
                    Object.defineProperty(this, key, def);
                }
            }
        };

        function makeComputedGetter(getter, owner) {
            var watcher = new Watcher(owner, getter, null, {
                lazy: true
            });
            return function computedGetter() {
                if (watcher.dirty) {
                    watcher.evaluate();
                }
                if (Dep.target) {
                    watcher.depend();
                }
                return watcher.value;
            };
        }

        /**
         * Setup instance methods. Methods must be bound to the
         * instance since they might be passed down as a prop to
         * child components.
         */

        Vue.prototype._initMethods = function() {
            var methods = this.$options.methods;
            if (methods) {
                for (var key in methods) {
                    this[key] = bind(methods[key], this);
                }
            }
        };

        /**
         * Initialize meta information like $index, $key & $value.
         */

        Vue.prototype._initMeta = function() {
            var metas = this.$options._meta;
            if (metas) {
                for (var key in metas) {
                    defineReactive(this, key, metas[key]);
                }
            }
        };
    }

    var eventRE = /^v-on:|^@/;

    function eventsMixin(Vue) {
        /**
         * Setup the instance's option events & watchers.
         * If the value is a string, we pull it from the
         * instance's methods by name.
         */

        Vue.prototype._initEvents = function() {
            var options = this.$options;
            if (options._asComponent) {
                registerComponentEvents(this, options.el);
            }
            registerCallbacks(this, '$on', options.events);
            registerCallbacks(this, '$watch', options.watch);
        };

        /**
         * Register v-on events on a child component
         *
         * @param {Vue} vm
         * @param {Element} el
         */

        function registerComponentEvents(vm, el) {
            var attrs = el.attributes;
            var name, value, handler;
            for (var i = 0, l = attrs.length; i < l; i++) {
                name = attrs[i].name;
                if (eventRE.test(name)) {
                    name = name.replace(eventRE, '');
                    // force the expression into a statement so that
                    // it always dynamically resolves the method to call (#2670)
                    // kinda ugly hack, but does the job.
                    value = attrs[i].value;
                    if (isSimplePath(value)) {
                        value += '.apply(this, $arguments)';
                    }
                    handler = (vm._scope || vm._context).$eval(value, true);
                    handler._fromParent = true;
                    vm.$on(name.replace(eventRE), handler);
                }
            }
        }

        /**
         * Register callbacks for option events and watchers.
         *
         * @param {Vue} vm
         * @param {String} action
         * @param {Object} hash
         */

        function registerCallbacks(vm, action, hash) {
            if (!hash) return;
            var handlers, key, i, j;
            for (key in hash) {
                handlers = hash[key];
                if (isArray(handlers)) {
                    for (i = 0, j = handlers.length; i < j; i++) {
                        register(vm, action, key, handlers[i]);
                    }
                } else {
                    register(vm, action, key, handlers);
                }
            }
        }

        /**
         * Helper to register an event/watch callback.
         *
         * @param {Vue} vm
         * @param {String} action
         * @param {String} key
         * @param {Function|String|Object} handler
         * @param {Object} [options]
         */

        function register(vm, action, key, handler, options) {
            var type = typeof handler;
            if (type === 'function') {
                vm[action](key, handler, options);
            } else if (type === 'string') {
                var methods = vm.$options.methods;
                var method = methods && methods[handler];
                if (method) {
                    vm[action](key, method, options);
                } else {
                    'development' !== 'production' && warn('Unknown method: "' + handler + '" when ' + 'registering callback for ' + action + ': "' + key + '".', vm);
                }
            } else if (handler && type === 'object') {
                register(vm, action, key, handler.handler, handler);
            }
        }

        /**
         * Setup recursive attached/detached calls
         */

        Vue.prototype._initDOMHooks = function() {
            this.$on('hook:attached', onAttached);
            this.$on('hook:detached', onDetached);
        };

        /**
         * Callback to recursively call attached hook on children
         */

        function onAttached() {
            if (!this._isAttached) {
                this._isAttached = true;
                this.$children.forEach(callAttach);
            }
        }

        /**
         * Iterator to call attached hook
         *
         * @param {Vue} child
         */

        function callAttach(child) {
            if (!child._isAttached && inDoc(child.$el)) {
                child._callHook('attached');
            }
        }

        /**
         * Callback to recursively call detached hook on children
         */

        function onDetached() {
            if (this._isAttached) {
                this._isAttached = false;
                this.$children.forEach(callDetach);
            }
        }

        /**
         * Iterator to call detached hook
         *
         * @param {Vue} child
         */

        function callDetach(child) {
            if (child._isAttached && !inDoc(child.$el)) {
                child._callHook('detached');
            }
        }

        /**
         * Trigger all handlers for a hook
         *
         * @param {String} hook
         */

        Vue.prototype._callHook = function(hook) {
            this.$emit('pre-hook:' + hook);
            var handlers = this.$options[hook];
            if (handlers) {
                for (var i = 0, j = handlers.length; i < j; i++) {
                    handlers[i].call(this);
                }
            }
            this.$emit('hook:' + hook);
        };
    }

    function noop() {}

    /**
     * A directive links a DOM element with a piece of data,
     * which is the result of evaluating an expression.
     * It registers a watcher with the expression and calls
     * the DOM update function when a change is triggered.
     *
     * @param {Object} descriptor
     *                 - {String} name
     *                 - {Object} def
     *                 - {String} expression
     *                 - {Array<Object>} [filters]
     *                 - {Object} [modifiers]
     *                 - {Boolean} literal
     *                 - {String} attr
     *                 - {String} arg
     *                 - {String} raw
     *                 - {String} [ref]
     *                 - {Array<Object>} [interp]
     *                 - {Boolean} [hasOneTime]
     * @param {Vue} vm
     * @param {Node} el
     * @param {Vue} [host] - transclusion host component
     * @param {Object} [scope] - v-for scope
     * @param {Fragment} [frag] - owner fragment
     * @constructor
     */
    function Directive(descriptor, vm, el, host, scope, frag) {
        this.vm = vm;
        this.el = el;
        // copy descriptor properties
        this.descriptor = descriptor;
        this.name = descriptor.name;
        this.expression = descriptor.expression;
        this.arg = descriptor.arg;
        this.modifiers = descriptor.modifiers;
        this.filters = descriptor.filters;
        this.literal = this.modifiers && this.modifiers.literal;
        // private
        this._locked = false;
        this._bound = false;
        this._listeners = null;
        // link context
        this._host = host;
        this._scope = scope;
        this._frag = frag;
        // store directives on node in dev mode
        if ('development' !== 'production' && this.el) {
            this.el._vue_directives = this.el._vue_directives || [];
            this.el._vue_directives.push(this);
        }
    }

    /**
     * Initialize the directive, mixin definition properties,
     * setup the watcher, call definition bind() and update()
     * if present.
     */

    Directive.prototype._bind = function() {
        var name = this.name;
        var descriptor = this.descriptor;

        // remove attribute
        if ((name !== 'cloak' || this.vm._isCompiled) && this.el && this.el.removeAttribute) {
            var attr = descriptor.attr || 'v-' + name;
            this.el.removeAttribute(attr);
        }

        // copy def properties
        var def = descriptor.def;
        if (typeof def === 'function') {
            this.update = def;
        } else {
            extend(this, def);
        }

        // setup directive params
        this._setupParams();

        // initial bind
        if (this.bind) {
            this.bind();
        }
        this._bound = true;

        if (this.literal) {
            this.update && this.update(descriptor.raw);
        } else if ((this.expression || this.modifiers) && (this.update || this.twoWay) && !this._checkStatement()) {
            // wrapped updater for context
            var dir = this;
            if (this.update) {
                this._update = function(val, oldVal) {
                    if (!dir._locked) {
                        dir.update(val, oldVal);
                    }
                };
            } else {
                this._update = noop;
            }
            var preProcess = this._preProcess ? bind(this._preProcess, this) : null;
            var postProcess = this._postProcess ? bind(this._postProcess, this) : null;
            var watcher = this._watcher = new Watcher(this.vm, this.expression, this._update, // callback
                {
                    filters: this.filters,
                    twoWay: this.twoWay,
                    deep: this.deep,
                    preProcess: preProcess,
                    postProcess: postProcess,
                    scope: this._scope
                });
            // v-model with inital inline value need to sync back to
            // model instead of update to DOM on init. They would
            // set the afterBind hook to indicate that.
            if (this.afterBind) {
                this.afterBind();
            } else if (this.update) {
                this.update(watcher.value);
            }
        }
    };

    /**
     * Setup all param attributes, e.g. track-by,
     * transition-mode, etc...
     */

    Directive.prototype._setupParams = function() {
        if (!this.params) {
            return;
        }
        var params = this.params;
        // swap the params array with a fresh object.
        this.params = Object.create(null);
        var i = params.length;
        var key, val, mappedKey;
        while (i--) {
            key = hyphenate(params[i]);
            mappedKey = camelize(key);
            val = getBindAttr(this.el, key);
            if (val != null) {
                // dynamic
                this._setupParamWatcher(mappedKey, val);
            } else {
                // static
                val = getAttr(this.el, key);
                if (val != null) {
                    this.params[mappedKey] = val === '' ? true : val;
                }
            }
        }
    };

    /**
     * Setup a watcher for a dynamic param.
     *
     * @param {String} key
     * @param {String} expression
     */

    Directive.prototype._setupParamWatcher = function(key, expression) {
        var self = this;
        var called = false;
        var unwatch = (this._scope || this.vm).$watch(expression, function(val, oldVal) {
            self.params[key] = val;
            // since we are in immediate mode,
            // only call the param change callbacks if this is not the first update.
            if (called) {
                var cb = self.paramWatchers && self.paramWatchers[key];
                if (cb) {
                    cb.call(self, val, oldVal);
                }
            } else {
                called = true;
            }
        }, {
            immediate: true,
            user: false
        });
        (this._paramUnwatchFns || (this._paramUnwatchFns = [])).push(unwatch);
    };

    /**
     * Check if the directive is a function caller
     * and if the expression is a callable one. If both true,
     * we wrap up the expression and use it as the event
     * handler.
     *
     * e.g. on-click="a++"
     *
     * @return {Boolean}
     */

    Directive.prototype._checkStatement = function() {
        var expression = this.expression;
        if (expression && this.acceptStatement && !isSimplePath(expression)) {
            var fn = parseExpression(expression).get;
            var scope = this._scope || this.vm;
            var handler = function handler(e) {
                scope.$event = e;
                fn.call(scope, scope);
                scope.$event = null;
            };
            if (this.filters) {
                handler = scope._applyFilters(handler, null, this.filters);
            }
            this.update(handler);
            return true;
        }
    };

    /**
     * Set the corresponding value with the setter.
     * This should only be used in two-way directives
     * e.g. v-model.
     *
     * @param {*} value
     * @public
     */

    Directive.prototype.set = function(value) {
        /* istanbul ignore else */
        if (this.twoWay) {
            this._withLock(function() {
                this._watcher.set(value);
            });
        } else if ('development' !== 'production') {
            warn('Directive.set() can only be used inside twoWay' + 'directives.');
        }
    };

    /**
     * Execute a function while preventing that function from
     * triggering updates on this directive instance.
     *
     * @param {Function} fn
     */

    Directive.prototype._withLock = function(fn) {
        var self = this;
        self._locked = true;
        fn.call(self);
        nextTick(function() {
            self._locked = false;
        });
    };

    /**
     * Convenience method that attaches a DOM event listener
     * to the directive element and autometically tears it down
     * during unbind.
     *
     * @param {String} event
     * @param {Function} handler
     * @param {Boolean} [useCapture]
     */

    Directive.prototype.on = function(event, handler, useCapture) {
        on(this.el, event, handler, useCapture);
        (this._listeners || (this._listeners = [])).push([event, handler]);
    };

    /**
     * Teardown the watcher and call unbind.
     */

    Directive.prototype._teardown = function() {
        if (this._bound) {
            this._bound = false;
            if (this.unbind) {
                this.unbind();
            }
            if (this._watcher) {
                this._watcher.teardown();
            }
            var listeners = this._listeners;
            var i;
            if (listeners) {
                i = listeners.length;
                while (i--) {
                    off(this.el, listeners[i][0], listeners[i][1]);
                }
            }
            var unwatchFns = this._paramUnwatchFns;
            if (unwatchFns) {
                i = unwatchFns.length;
                while (i--) {
                    unwatchFns[i]();
                }
            }
            if ('development' !== 'production' && this.el) {
                this.el._vue_directives.$remove(this);
            }
            this.vm = this.el = this._watcher = this._listeners = null;
        }
    };

    function lifecycleMixin(Vue) {
        /**
         * Update v-ref for component.
         *
         * @param {Boolean} remove
         */

        Vue.prototype._updateRef = function(remove) {
            var ref = this.$options._ref;
            if (ref) {
                var refs = (this._scope || this._context).$refs;
                if (remove) {
                    if (refs[ref] === this) {
                        refs[ref] = null;
                    }
                } else {
                    refs[ref] = this;
                }
            }
        };

        /**
         * Transclude, compile and link element.
         *
         * If a pre-compiled linker is available, that means the
         * passed in element will be pre-transcluded and compiled
         * as well - all we need to do is to call the linker.
         *
         * Otherwise we need to call transclude/compile/link here.
         *
         * @param {Element} el
         */

        Vue.prototype._compile = function(el) {
            var options = this.$options;

            // transclude and init element
            // transclude can potentially replace original
            // so we need to keep reference; this step also injects
            // the template and caches the original attributes
            // on the container node and replacer node.
            var original = el;
            el = transclude(el, options);
            this._initElement(el);

            // handle v-pre on root node (#2026)
            if (el.nodeType === 1 && getAttr(el, 'v-pre') !== null) {
                return;
            }

            // root is always compiled per-instance, because
            // container attrs and props can be different every time.
            var contextOptions = this._context && this._context.$options;
            var rootLinker = compileRoot(el, options, contextOptions);

            // resolve slot distribution
            resolveSlots(this, options._content);

            // compile and link the rest
            var contentLinkFn;
            var ctor = this.constructor;
            // component compilation can be cached
            // as long as it's not using inline-template
            if (options._linkerCachable) {
                contentLinkFn = ctor.linker;
                if (!contentLinkFn) {
                    contentLinkFn = ctor.linker = compile(el, options);
                }
            }

            // link phase
            // make sure to link root with prop scope!
            var rootUnlinkFn = rootLinker(this, el, this._scope);
            var contentUnlinkFn = contentLinkFn ? contentLinkFn(this, el) : compile(el, options)(this, el);

            // register composite unlink function
            // to be called during instance destruction
            this._unlinkFn = function() {
                rootUnlinkFn();
                // passing destroying: true to avoid searching and
                // splicing the directives
                contentUnlinkFn(true);
            };

            // finally replace original
            if (options.replace) {
                replace(original, el);
            }

            this._isCompiled = true;
            this._callHook('compiled');
        };

        /**
         * Initialize instance element. Called in the public
         * $mount() method.
         *
         * @param {Element} el
         */

        Vue.prototype._initElement = function(el) {
            if (isFragment(el)) {
                this._isFragment = true;
                this.$el = this._fragmentStart = el.firstChild;
                this._fragmentEnd = el.lastChild;
                // set persisted text anchors to empty
                if (this._fragmentStart.nodeType === 3) {
                    this._fragmentStart.data = this._fragmentEnd.data = '';
                }
                this._fragment = el;
            } else {
                this.$el = el;
            }
            this.$el.__vue__ = this;
            this._callHook('beforeCompile');
        };

        /**
         * Create and bind a directive to an element.
         *
         * @param {Object} descriptor - parsed directive descriptor
         * @param {Node} node   - target node
         * @param {Vue} [host] - transclusion host component
         * @param {Object} [scope] - v-for scope
         * @param {Fragment} [frag] - owner fragment
         */

        Vue.prototype._bindDir = function(descriptor, node, host, scope, frag) {
            this._directives.push(new Directive(descriptor, this, node, host, scope, frag));
        };

        /**
         * Teardown an instance, unobserves the data, unbind all the
         * directives, turn off all the event listeners, etc.
         *
         * @param {Boolean} remove - whether to remove the DOM node.
         * @param {Boolean} deferCleanup - if true, defer cleanup to
         *                                 be called later
         */

        Vue.prototype._destroy = function(remove, deferCleanup) {
            if (this._isBeingDestroyed) {
                if (!deferCleanup) {
                    this._cleanup();
                }
                return;
            }

            var destroyReady;
            var pendingRemoval;

            var self = this;
            // Cleanup should be called either synchronously or asynchronoysly as
            // callback of this.$remove(), or if remove and deferCleanup are false.
            // In any case it should be called after all other removing, unbinding and
            // turning of is done
            var cleanupIfPossible = function cleanupIfPossible() {
                if (destroyReady && !pendingRemoval && !deferCleanup) {
                    self._cleanup();
                }
            };

            // remove DOM element
            if (remove && this.$el) {
                pendingRemoval = true;
                this.$remove(function() {
                    pendingRemoval = false;
                    cleanupIfPossible();
                });
            }

            this._callHook('beforeDestroy');
            this._isBeingDestroyed = true;
            var i;
            // remove self from parent. only necessary
            // if parent is not being destroyed as well.
            var parent = this.$parent;
            if (parent && !parent._isBeingDestroyed) {
                parent.$children.$remove(this);
                // unregister ref (remove: true)
                this._updateRef(true);
            }
            // destroy all children.
            i = this.$children.length;
            while (i--) {
                this.$children[i].$destroy();
            }
            // teardown props
            if (this._propsUnlinkFn) {
                this._propsUnlinkFn();
            }
            // teardown all directives. this also tearsdown all
            // directive-owned watchers.
            if (this._unlinkFn) {
                this._unlinkFn();
            }
            i = this._watchers.length;
            while (i--) {
                this._watchers[i].teardown();
            }
            // remove reference to self on $el
            if (this.$el) {
                this.$el.__vue__ = null;
            }

            destroyReady = true;
            cleanupIfPossible();
        };

        /**
         * Clean up to ensure garbage collection.
         * This is called after the leave transition if there
         * is any.
         */

        Vue.prototype._cleanup = function() {
            if (this._isDestroyed) {
                return;
            }
            // remove self from owner fragment
            // do it in cleanup so that we can call $destroy with
            // defer right when a fragment is about to be removed.
            if (this._frag) {
                this._frag.children.$remove(this);
            }
            // remove reference from data ob
            // frozen object may not have observer.
            if (this._data && this._data.__ob__) {
                this._data.__ob__.removeVm(this);
            }
            // Clean up references to private properties and other
            // instances. preserve reference to _data so that proxy
            // accessors still work. The only potential side effect
            // here is that mutating the instance after it's destroyed
            // may affect the state of other components that are still
            // observing the same object, but that seems to be a
            // reasonable responsibility for the user rather than
            // always throwing an error on them.
            this.$el = this.$parent = this.$root = this.$children = this._watchers = this._context = this._scope = this._directives = null;
            // call the last hook...
            this._isDestroyed = true;
            this._callHook('destroyed');
            // turn off all instance listeners.
            this.$off();
        };
    }

    function miscMixin(Vue) {
        /**
         * Apply a list of filter (descriptors) to a value.
         * Using plain for loops here because this will be called in
         * the getter of any watcher with filters so it is very
         * performance sensitive.
         *
         * @param {*} value
         * @param {*} [oldValue]
         * @param {Array} filters
         * @param {Boolean} write
         * @return {*}
         */

        Vue.prototype._applyFilters = function(value, oldValue, filters, write) {
            var filter, fn, args, arg, offset, i, l, j, k;
            for (i = 0, l = filters.length; i < l; i++) {
                filter = filters[write ? l - i - 1 : i];
                fn = resolveAsset(this.$options, 'filters', filter.name, true);
                if (!fn) continue;
                fn = write ? fn.write : fn.read || fn;
                if (typeof fn !== 'function') continue;
                args = write ? [value, oldValue] : [value];
                offset = write ? 2 : 1;
                if (filter.args) {
                    for (j = 0, k = filter.args.length; j < k; j++) {
                        arg = filter.args[j];
                        args[j + offset] = arg.dynamic ? this.$get(arg.value) : arg.value;
                    }
                }
                value = fn.apply(this, args);
            }
            return value;
        };

        /**
         * Resolve a component, depending on whether the component
         * is defined normally or using an async factory function.
         * Resolves synchronously if already resolved, otherwise
         * resolves asynchronously and caches the resolved
         * constructor on the factory.
         *
         * @param {String|Function} value
         * @param {Function} cb
         */

        Vue.prototype._resolveComponent = function(value, cb) {
            var factory;
            if (typeof value === 'function') {
                factory = value;
            } else {
                factory = resolveAsset(this.$options, 'components', value, true);
            }
            /* istanbul ignore if */
            if (!factory) {
                return;
            }
            // async component factory
            if (!factory.options) {
                if (factory.resolved) {
                    // cached
                    cb(factory.resolved);
                } else if (factory.requested) {
                    // pool callbacks
                    factory.pendingCallbacks.push(cb);
                } else {
                    factory.requested = true;
                    var cbs = factory.pendingCallbacks = [cb];
                    factory.call(this, function resolve(res) {
                        if (isPlainObject(res)) {
                            res = Vue.extend(res);
                        }
                        // cache resolved
                        factory.resolved = res;
                        // invoke callbacks
                        for (var i = 0, l = cbs.length; i < l; i++) {
                            cbs[i](res);
                        }
                    }, function reject(reason) {
                        'development' !== 'production' && warn('Failed to resolve async component' + (typeof value === 'string' ? ': ' + value : '') + '. ' + (reason ? '\nReason: ' + reason : ''));
                    });
                }
            } else {
                // normal component
                cb(factory);
            }
        };
    }

    var filterRE$1 = /[^|]\|[^|]/;

    function dataAPI(Vue) {
        /**
         * Get the value from an expression on this vm.
         *
         * @param {String} exp
         * @param {Boolean} [asStatement]
         * @return {*}
         */

        Vue.prototype.$get = function(exp, asStatement) {
            var res = parseExpression(exp);
            if (res) {
                if (asStatement) {
                    var self = this;
                    return function statementHandler() {
                        self.$arguments = toArray(arguments);
                        var result = res.get.call(self, self);
                        self.$arguments = null;
                        return result;
                    };
                } else {
                    try {
                        return res.get.call(this, this);
                    } catch (e) {}
                }
            }
        };

        /**
         * Set the value from an expression on this vm.
         * The expression must be a valid left-hand
         * expression in an assignment.
         *
         * @param {String} exp
         * @param {*} val
         */

        Vue.prototype.$set = function(exp, val) {
            var res = parseExpression(exp, true);
            if (res && res.set) {
                res.set.call(this, this, val);
            }
        };

        /**
         * Delete a property on the VM
         *
         * @param {String} key
         */

        Vue.prototype.$delete = function(key) {
            del(this._data, key);
        };

        /**
         * Watch an expression, trigger callback when its
         * value changes.
         *
         * @param {String|Function} expOrFn
         * @param {Function} cb
         * @param {Object} [options]
         *                 - {Boolean} deep
         *                 - {Boolean} immediate
         * @return {Function} - unwatchFn
         */

        Vue.prototype.$watch = function(expOrFn, cb, options) {
            var vm = this;
            var parsed;
            if (typeof expOrFn === 'string') {
                parsed = parseDirective(expOrFn);
                expOrFn = parsed.expression;
            }
            var watcher = new Watcher(vm, expOrFn, cb, {
                deep: options && options.deep,
                sync: options && options.sync,
                filters: parsed && parsed.filters,
                user: !options || options.user !== false
            });
            if (options && options.immediate) {
                cb.call(vm, watcher.value);
            }
            return function unwatchFn() {
                watcher.teardown();
            };
        };

        /**
         * Evaluate a text directive, including filters.
         *
         * @param {String} text
         * @param {Boolean} [asStatement]
         * @return {String}
         */

        Vue.prototype.$eval = function(text, asStatement) {
            // check for filters.
            if (filterRE$1.test(text)) {
                var dir = parseDirective(text);
                // the filter regex check might give false positive
                // for pipes inside strings, so it's possible that
                // we don't get any filters here
                var val = this.$get(dir.expression, asStatement);
                return dir.filters ? this._applyFilters(val, null, dir.filters) : val;
            } else {
                // no filter
                return this.$get(text, asStatement);
            }
        };

        /**
         * Interpolate a piece of template text.
         *
         * @param {String} text
         * @return {String}
         */

        Vue.prototype.$interpolate = function(text) {
            var tokens = parseText(text);
            var vm = this;
            if (tokens) {
                if (tokens.length === 1) {
                    return vm.$eval(tokens[0].value) + '';
                } else {
                    return tokens.map(function(token) {
                        return token.tag ? vm.$eval(token.value) : token.value;
                    }).join('');
                }
            } else {
                return text;
            }
        };

        /**
         * Log instance data as a plain JS object
         * so that it is easier to inspect in console.
         * This method assumes console is available.
         *
         * @param {String} [path]
         */

        Vue.prototype.$log = function(path) {
            var data = path ? getPath(this._data, path) : this._data;
            if (data) {
                data = clean(data);
            }
            // include computed fields
            if (!path) {
                var key;
                for (key in this.$options.computed) {
                    data[key] = clean(this[key]);
                }
                if (this._props) {
                    for (key in this._props) {
                        data[key] = clean(this[key]);
                    }
                }
            }
            console.log(data);
        };

        /**
         * "clean" a getter/setter converted object into a plain
         * object copy.
         *
         * @param {Object} - obj
         * @return {Object}
         */

        function clean(obj) {
            return JSON.parse(JSON.stringify(obj));
        }
    }

    function domAPI(Vue) {
        /**
         * Convenience on-instance nextTick. The callback is
         * auto-bound to the instance, and this avoids component
         * modules having to rely on the global Vue.
         *
         * @param {Function} fn
         */

        Vue.prototype.$nextTick = function(fn) {
            nextTick(fn, this);
        };

        /**
         * Append instance to target
         *
         * @param {Node} target
         * @param {Function} [cb]
         * @param {Boolean} [withTransition] - defaults to true
         */

        Vue.prototype.$appendTo = function(target, cb, withTransition) {
            return insert(this, target, cb, withTransition, append, appendWithTransition);
        };

        /**
         * Prepend instance to target
         *
         * @param {Node} target
         * @param {Function} [cb]
         * @param {Boolean} [withTransition] - defaults to true
         */

        Vue.prototype.$prependTo = function(target, cb, withTransition) {
            target = query(target);
            if (target.hasChildNodes()) {
                this.$before(target.firstChild, cb, withTransition);
            } else {
                this.$appendTo(target, cb, withTransition);
            }
            return this;
        };

        /**
         * Insert instance before target
         *
         * @param {Node} target
         * @param {Function} [cb]
         * @param {Boolean} [withTransition] - defaults to true
         */

        Vue.prototype.$before = function(target, cb, withTransition) {
            return insert(this, target, cb, withTransition, beforeWithCb, beforeWithTransition);
        };

        /**
         * Insert instance after target
         *
         * @param {Node} target
         * @param {Function} [cb]
         * @param {Boolean} [withTransition] - defaults to true
         */

        Vue.prototype.$after = function(target, cb, withTransition) {
            target = query(target);
            if (target.nextSibling) {
                this.$before(target.nextSibling, cb, withTransition);
            } else {
                this.$appendTo(target.parentNode, cb, withTransition);
            }
            return this;
        };

        /**
         * Remove instance from DOM
         *
         * @param {Function} [cb]
         * @param {Boolean} [withTransition] - defaults to true
         */

        Vue.prototype.$remove = function(cb, withTransition) {
            if (!this.$el.parentNode) {
                return cb && cb();
            }
            var inDocument = this._isAttached && inDoc(this.$el);
            // if we are not in document, no need to check
            // for transitions
            if (!inDocument) withTransition = false;
            var self = this;
            var realCb = function realCb() {
                if (inDocument) self._callHook('detached');
                if (cb) cb();
            };
            if (this._isFragment) {
                removeNodeRange(this._fragmentStart, this._fragmentEnd, this, this._fragment, realCb);
            } else {
                var op = withTransition === false ? removeWithCb : removeWithTransition;
                op(this.$el, this, realCb);
            }
            return this;
        };

        /**
         * Shared DOM insertion function.
         *
         * @param {Vue} vm
         * @param {Element} target
         * @param {Function} [cb]
         * @param {Boolean} [withTransition]
         * @param {Function} op1 - op for non-transition insert
         * @param {Function} op2 - op for transition insert
         * @return vm
         */

        function insert(vm, target, cb, withTransition, op1, op2) {
            target = query(target);
            var targetIsDetached = !inDoc(target);
            var op = withTransition === false || targetIsDetached ? op1 : op2;
            var shouldCallHook = !targetIsDetached && !vm._isAttached && !inDoc(vm.$el);
            if (vm._isFragment) {
                mapNodeRange(vm._fragmentStart, vm._fragmentEnd, function(node) {
                    op(node, target, vm);
                });
                cb && cb();
            } else {
                op(vm.$el, target, vm, cb);
            }
            if (shouldCallHook) {
                vm._callHook('attached');
            }
            return vm;
        }

        /**
         * Check for selectors
         *
         * @param {String|Element} el
         */

        function query(el) {
            return typeof el === 'string' ? document.querySelector(el) : el;
        }

        /**
         * Append operation that takes a callback.
         *
         * @param {Node} el
         * @param {Node} target
         * @param {Vue} vm - unused
         * @param {Function} [cb]
         */

        function append(el, target, vm, cb) {
            target.appendChild(el);
            if (cb) cb();
        }

        /**
         * InsertBefore operation that takes a callback.
         *
         * @param {Node} el
         * @param {Node} target
         * @param {Vue} vm - unused
         * @param {Function} [cb]
         */

        function beforeWithCb(el, target, vm, cb) {
            before(el, target);
            if (cb) cb();
        }

        /**
         * Remove operation that takes a callback.
         *
         * @param {Node} el
         * @param {Vue} vm - unused
         * @param {Function} [cb]
         */

        function removeWithCb(el, vm, cb) {
            remove(el);
            if (cb) cb();
        }
    }

    function eventsAPI(Vue) {
        /**
         * Listen on the given `event` with `fn`.
         *
         * @param {String} event
         * @param {Function} fn
         */

        Vue.prototype.$on = function(event, fn) {
            (this._events[event] || (this._events[event] = [])).push(fn);
            modifyListenerCount(this, event, 1);
            return this;
        };

        /**
         * Adds an `event` listener that will be invoked a single
         * time then automatically removed.
         *
         * @param {String} event
         * @param {Function} fn
         */

        Vue.prototype.$once = function(event, fn) {
            var self = this;

            function on() {
                self.$off(event, on);
                fn.apply(this, arguments);
            }
            on.fn = fn;
            this.$on(event, on);
            return this;
        };

        /**
         * Remove the given callback for `event` or all
         * registered callbacks.
         *
         * @param {String} event
         * @param {Function} fn
         */

        Vue.prototype.$off = function(event, fn) {
            var cbs;
            // all
            if (!arguments.length) {
                if (this.$parent) {
                    for (event in this._events) {
                        cbs = this._events[event];
                        if (cbs) {
                            modifyListenerCount(this, event, -cbs.length);
                        }
                    }
                }
                this._events = {};
                return this;
            }
            // specific event
            cbs = this._events[event];
            if (!cbs) {
                return this;
            }
            if (arguments.length === 1) {
                modifyListenerCount(this, event, -cbs.length);
                this._events[event] = null;
                return this;
            }
            // specific handler
            var cb;
            var i = cbs.length;
            while (i--) {
                cb = cbs[i];
                if (cb === fn || cb.fn === fn) {
                    modifyListenerCount(this, event, -1);
                    cbs.splice(i, 1);
                    break;
                }
            }
            return this;
        };

        /**
         * Trigger an event on self.
         *
         * @param {String|Object} event
         * @return {Boolean} shouldPropagate
         */

        Vue.prototype.$emit = function(event) {
            var isSource = typeof event === 'string';
            event = isSource ? event : event.name;
            var cbs = this._events[event];
            var shouldPropagate = isSource || !cbs;
            if (cbs) {
                cbs = cbs.length > 1 ? toArray(cbs) : cbs;
                // this is a somewhat hacky solution to the question raised
                // in #2102: for an inline component listener like <comp @test="doThis">,
                // the propagation handling is somewhat broken. Therefore we
                // need to treat these inline callbacks differently.
                var hasParentCbs = isSource && cbs.some(function(cb) {
                    return cb._fromParent;
                });
                if (hasParentCbs) {
                    shouldPropagate = false;
                }
                var args = toArray(arguments, 1);
                for (var i = 0, l = cbs.length; i < l; i++) {
                    var cb = cbs[i];
                    var res = cb.apply(this, args);
                    if (res === true && (!hasParentCbs || cb._fromParent)) {
                        shouldPropagate = true;
                    }
                }
            }
            return shouldPropagate;
        };

        /**
         * Recursively broadcast an event to all children instances.
         *
         * @param {String|Object} event
         * @param {...*} additional arguments
         */

        Vue.prototype.$broadcast = function(event) {
            var isSource = typeof event === 'string';
            event = isSource ? event : event.name;
            // if no child has registered for this event,
            // then there's no need to broadcast.
            if (!this._eventsCount[event]) return;
            var children = this.$children;
            var args = toArray(arguments);
            if (isSource) {
                // use object event to indicate non-source emit
                // on children
                args[0] = {
                    name: event,
                    source: this
                };
            }
            for (var i = 0, l = children.length; i < l; i++) {
                var child = children[i];
                var shouldPropagate = child.$emit.apply(child, args);
                if (shouldPropagate) {
                    child.$broadcast.apply(child, args);
                }
            }
            return this;
        };

        /**
         * Recursively propagate an event up the parent chain.
         *
         * @param {String} event
         * @param {...*} additional arguments
         */

        Vue.prototype.$dispatch = function(event) {
            var shouldPropagate = this.$emit.apply(this, arguments);
            if (!shouldPropagate) return;
            var parent = this.$parent;
            var args = toArray(arguments);
            // use object event to indicate non-source emit
            // on parents
            args[0] = {
                name: event,
                source: this
            };
            while (parent) {
                shouldPropagate = parent.$emit.apply(parent, args);
                parent = shouldPropagate ? parent.$parent : null;
            }
            return this;
        };

        /**
         * Modify the listener counts on all parents.
         * This bookkeeping allows $broadcast to return early when
         * no child has listened to a certain event.
         *
         * @param {Vue} vm
         * @param {String} event
         * @param {Number} count
         */

        var hookRE = /^hook:/;

        function modifyListenerCount(vm, event, count) {
            var parent = vm.$parent;
            // hooks do not get broadcasted so no need
            // to do bookkeeping for them
            if (!parent || !count || hookRE.test(event)) return;
            while (parent) {
                parent._eventsCount[event] = (parent._eventsCount[event] || 0) + count;
                parent = parent.$parent;
            }
        }
    }

    function lifecycleAPI(Vue) {
        /**
         * Set instance target element and kick off the compilation
         * process. The passed in `el` can be a selector string, an
         * existing Element, or a DocumentFragment (for block
         * instances).
         *
         * @param {Element|DocumentFragment|string} el
         * @public
         */

        Vue.prototype.$mount = function(el) {
            if (this._isCompiled) {
                'development' !== 'production' && warn('$mount() should be called only once.', this);
                return;
            }
            el = query(el);
            if (!el) {
                el = document.createElement('div');
            }
            this._compile(el);
            this._initDOMHooks();
            if (inDoc(this.$el)) {
                this._callHook('attached');
                ready.call(this);
            } else {
                this.$once('hook:attached', ready);
            }
            return this;
        };

        /**
         * Mark an instance as ready.
         */

        function ready() {
            this._isAttached = true;
            this._isReady = true;
            this._callHook('ready');
        }

        /**
         * Teardown the instance, simply delegate to the internal
         * _destroy.
         *
         * @param {Boolean} remove
         * @param {Boolean} deferCleanup
         */

        Vue.prototype.$destroy = function(remove, deferCleanup) {
            this._destroy(remove, deferCleanup);
        };

        /**
         * Partially compile a piece of DOM and return a
         * decompile function.
         *
         * @param {Element|DocumentFragment} el
         * @param {Vue} [host]
         * @param {Object} [scope]
         * @param {Fragment} [frag]
         * @return {Function}
         */

        Vue.prototype.$compile = function(el, host, scope, frag) {
            return compile(el, this.$options, true)(this, el, host, scope, frag);
        };
    }

    /**
     * The exposed Vue constructor.
     *
     * API conventions:
     * - public API methods/properties are prefixed with `$`
     * - internal methods/properties are prefixed with `_`
     * - non-prefixed properties are assumed to be proxied user
     *   data.
     *
     * @constructor
     * @param {Object} [options]
     * @public
     */

    function Vue(options) {
        this._init(options);
    }

    // install internals
    initMixin(Vue);
    stateMixin(Vue);
    eventsMixin(Vue);
    lifecycleMixin(Vue);
    miscMixin(Vue);

    // install instance APIs
    dataAPI(Vue);
    domAPI(Vue);
    eventsAPI(Vue);
    lifecycleAPI(Vue);

    var slot = {

        priority: SLOT,
        params: ['name'],

        bind: function bind() {
            // this was resolved during component transclusion
            var name = this.params.name || 'default';
            var content = this.vm._slotContents && this.vm._slotContents[name];
            if (!content || !content.hasChildNodes()) {
                this.fallback();
            } else {
                this.compile(content.cloneNode(true), this.vm._context, this.vm);
            }
        },

        compile: function compile(content, context, host) {
            if (content && context) {
                if (this.el.hasChildNodes() && content.childNodes.length === 1 && content.childNodes[0].nodeType === 1 && content.childNodes[0].hasAttribute('v-if')) {
                    // if the inserted slot has v-if
                    // inject fallback content as the v-else
                    var elseBlock = document.createElement('template');
                    elseBlock.setAttribute('v-else', '');
                    elseBlock.innerHTML = this.el.innerHTML;
                    // the else block should be compiled in child scope
                    elseBlock._context = this.vm;
                    content.appendChild(elseBlock);
                }
                var scope = host ? host._scope : this._scope;
                this.unlink = context.$compile(content, host, scope, this._frag);
            }
            if (content) {
                replace(this.el, content);
            } else {
                remove(this.el);
            }
        },

        fallback: function fallback() {
            this.compile(extractContent(this.el, true), this.vm);
        },

        unbind: function unbind() {
            if (this.unlink) {
                this.unlink();
            }
        }
    };

    var partial = {

        priority: PARTIAL,

        params: ['name'],

        // watch changes to name for dynamic partials
        paramWatchers: {
            name: function name(value) {
                vIf.remove.call(this);
                if (value) {
                    this.insert(value);
                }
            }
        },

        bind: function bind() {
            this.anchor = createAnchor('v-partial');
            replace(this.el, this.anchor);
            this.insert(this.params.name);
        },

        insert: function insert(id) {
            var partial = resolveAsset(this.vm.$options, 'partials', id, true);
            if (partial) {
                this.factory = new FragmentFactory(this.vm, partial);
                vIf.insert.call(this);
            }
        },

        unbind: function unbind() {
            if (this.frag) {
                this.frag.destroy();
            }
        }
    };

    var elementDirectives = {
        slot: slot,
        partial: partial
    };

    var convertArray = vFor._postProcess;

    /**
     * Limit filter for arrays
     *
     * @param {Number} n
     * @param {Number} offset (Decimal expected)
     */

    function limitBy(arr, n, offset) {
        offset = offset ? parseInt(offset, 10) : 0;
        n = toNumber(n);
        return typeof n === 'number' ? arr.slice(offset, offset + n) : arr;
    }

    /**
     * Filter filter for arrays
     *
     * @param {String} search
     * @param {String} [delimiter]
     * @param {String} ...dataKeys
     */

    function filterBy(arr, search, delimiter) {
        arr = convertArray(arr);
        if (search == null) {
            return arr;
        }
        if (typeof search === 'function') {
            return arr.filter(search);
        }
        // cast to lowercase string
        search = ('' + search).toLowerCase();
        // allow optional `in` delimiter
        // because why not
        var n = delimiter === 'in' ? 3 : 2;
        // extract and flatten keys
        var keys = Array.prototype.concat.apply([], toArray(arguments, n));
        var res = [];
        var item, key, val, j;
        for (var i = 0, l = arr.length; i < l; i++) {
            item = arr[i];
            val = item && item.$value || item;
            j = keys.length;
            if (j) {
                while (j--) {
                    key = keys[j];
                    if (key === '$key' && contains(item.$key, search) || contains(getPath(val, key), search)) {
                        res.push(item);
                        break;
                    }
                }
            } else if (contains(item, search)) {
                res.push(item);
            }
        }
        return res;
    }

    /**
     * Filter filter for arrays
     *
     * @param {String|Array<String>|Function} ...sortKeys
     * @param {Number} [order]
     */

    function orderBy(arr) {
        var comparator = null;
        var sortKeys = undefined;
        arr = convertArray(arr);

        // determine order (last argument)
        var args = toArray(arguments, 1);
        var order = args[args.length - 1];
        if (typeof order === 'number') {
            order = order < 0 ? -1 : 1;
            args = args.length > 1 ? args.slice(0, -1) : args;
        } else {
            order = 1;
        }

        // determine sortKeys & comparator
        var firstArg = args[0];
        if (!firstArg) {
            return arr;
        } else if (typeof firstArg === 'function') {
            // custom comparator
            comparator = function(a, b) {
                return firstArg(a, b) * order;
            };
        } else {
            // string keys. flatten first
            sortKeys = Array.prototype.concat.apply([], args);
            comparator = function(a, b, i) {
                i = i || 0;
                return i >= sortKeys.length - 1 ? baseCompare(a, b, i) : baseCompare(a, b, i) || comparator(a, b, i + 1);
            };
        }

        function baseCompare(a, b, sortKeyIndex) {
            var sortKey = sortKeys[sortKeyIndex];
            if (sortKey) {
                if (sortKey !== '$key') {
                    if (isObject(a) && '$value' in a) a = a.$value;
                    if (isObject(b) && '$value' in b) b = b.$value;
                }
                a = isObject(a) ? getPath(a, sortKey) : a;
                b = isObject(b) ? getPath(b, sortKey) : b;
            }
            return a === b ? 0 : a > b ? order : -order;
        }

        // sort on a copy to avoid mutating original array
        return arr.slice().sort(comparator);
    }

    /**
     * String contain helper
     *
     * @param {*} val
     * @param {String} search
     */

    function contains(val, search) {
        var i;
        if (isPlainObject(val)) {
            var keys = Object.keys(val);
            i = keys.length;
            while (i--) {
                if (contains(val[keys[i]], search)) {
                    return true;
                }
            }
        } else if (isArray(val)) {
            i = val.length;
            while (i--) {
                if (contains(val[i], search)) {
                    return true;
                }
            }
        } else if (val != null) {
            return val.toString().toLowerCase().indexOf(search) > -1;
        }
    }

    var digitsRE = /(\d{3})(?=\d)/g;

    // asset collections must be a plain object.
    var filters = {

        orderBy: orderBy,
        filterBy: filterBy,
        limitBy: limitBy,

        /**
         * Stringify value.
         *
         * @param {Number} indent
         */

        json: {
            read: function read(value, indent) {
                return typeof value === 'string' ? value : JSON.stringify(value, null, Number(indent) || 2);
            },
            write: function write(value) {
                try {
                    return JSON.parse(value);
                } catch (e) {
                    return value;
                }
            }
        },

        /**
         * 'abc' => 'Abc'
         */

        capitalize: function capitalize(value) {
            if (!value && value !== 0) return '';
            value = value.toString();
            return value.charAt(0).toUpperCase() + value.slice(1);
        },

        /**
         * 'abc' => 'ABC'
         */

        uppercase: function uppercase(value) {
            return value || value === 0 ? value.toString().toUpperCase() : '';
        },

        /**
         * 'AbC' => 'abc'
         */

        lowercase: function lowercase(value) {
            return value || value === 0 ? value.toString().toLowerCase() : '';
        },

        /**
         * 12345 => $12,345.00
         *
         * @param {String} sign
         * @param {Number} decimals Decimal places
         */

        currency: function currency(value, _currency, decimals) {
            value = parseFloat(value);
            if (!isFinite(value) || !value && value !== 0) return '';
            _currency = _currency != null ? _currency : '$';
            decimals = decimals != null ? decimals : 2;
            var stringified = Math.abs(value).toFixed(decimals);
            var _int = decimals ? stringified.slice(0, -1 - decimals) : stringified;
            var i = _int.length % 3;
            var head = i > 0 ? _int.slice(0, i) + (_int.length > 3 ? ',' : '') : '';
            var _float = decimals ? stringified.slice(-1 - decimals) : '';
            var sign = value < 0 ? '-' : '';
            return sign + _currency + head + _int.slice(i).replace(digitsRE, '$1,') + _float;
        },

        /**
         * 'item' => 'items'
         *
         * @params
         *  an array of strings corresponding to
         *  the single, double, triple ... forms of the word to
         *  be pluralized. When the number to be pluralized
         *  exceeds the length of the args, it will use the last
         *  entry in the array.
         *
         *  e.g. ['single', 'double', 'triple', 'multiple']
         */

        pluralize: function pluralize(value) {
            var args = toArray(arguments, 1);
            return args.length > 1 ? args[value % 10 - 1] || args[args.length - 1] : args[0] + (value === 1 ? '' : 's');
        },

        /**
         * Debounce a handler function.
         *
         * @param {Function} handler
         * @param {Number} delay = 300
         * @return {Function}
         */

        debounce: function debounce(handler, delay) {
            if (!handler) return;
            if (!delay) {
                delay = 300;
            }
            return _debounce(handler, delay);
        }
    };

    function installGlobalAPI(Vue) {
        /**
         * Vue and every constructor that extends Vue has an
         * associated options object, which can be accessed during
         * compilation steps as `this.constructor.options`.
         *
         * These can be seen as the default options of every
         * Vue instance.
         */

        Vue.options = {
            directives: directives,
            elementDirectives: elementDirectives,
            filters: filters,
            transitions: {},
            components: {},
            partials: {},
            replace: true
        };

        /**
         * Expose useful internals
         */

        Vue.util = util;
        Vue.config = config;
        Vue.set = set;
        Vue['delete'] = del;
        Vue.nextTick = nextTick;

        /**
         * The following are exposed for advanced usage / plugins
         */

        Vue.compiler = compiler;
        Vue.FragmentFactory = FragmentFactory;
        Vue.internalDirectives = internalDirectives;
        Vue.parsers = {
            path: path,
            text: text,
            template: template,
            directive: directive,
            expression: expression
        };

        /**
         * Each instance constructor, including Vue, has a unique
         * cid. This enables us to create wrapped "child
         * constructors" for prototypal inheritance and cache them.
         */

        Vue.cid = 0;
        var cid = 1;

        /**
         * Class inheritance
         *
         * @param {Object} extendOptions
         */

        Vue.extend = function(extendOptions) {
            extendOptions = extendOptions || {};
            var Super = this;
            var isFirstExtend = Super.cid === 0;
            if (isFirstExtend && extendOptions._Ctor) {
                return extendOptions._Ctor;
            }
            var name = extendOptions.name || Super.options.name;
            if ('development' !== 'production') {
                if (!/^[a-zA-Z][\w-]*$/.test(name)) {
                    warn('Invalid component name: "' + name + '". Component names ' + 'can only contain alphanumeric characaters and the hyphen.');
                    name = null;
                }
            }
            var Sub = createClass(name || 'VueComponent');
            Sub.prototype = Object.create(Super.prototype);
            Sub.prototype.constructor = Sub;
            Sub.cid = cid++;
            Sub.options = mergeOptions(Super.options, extendOptions);
            Sub['super'] = Super;
            // allow further extension
            Sub.extend = Super.extend;
            // create asset registers, so extended classes
            // can have their private assets too.
            config._assetTypes.forEach(function(type) {
                Sub[type] = Super[type];
            });
            // enable recursive self-lookup
            if (name) {
                Sub.options.components[name] = Sub;
            }
            // cache constructor
            if (isFirstExtend) {
                extendOptions._Ctor = Sub;
            }
            return Sub;
        };

        /**
         * A function that returns a sub-class constructor with the
         * given name. This gives us much nicer output when
         * logging instances in the console.
         *
         * @param {String} name
         * @return {Function}
         */

        function createClass(name) {
            /* eslint-disable no-new-func */
            return new Function('return function ' + classify(name) + ' (options) { this._init(options) }')();
            /* eslint-enable no-new-func */
        }

        /**
         * Plugin system
         *
         * @param {Object} plugin
         */

        Vue.use = function(plugin) {
            /* istanbul ignore if */
            if (plugin.installed) {
                return;
            }
            // additional parameters
            var args = toArray(arguments, 1);
            args.unshift(this);
            if (typeof plugin.install === 'function') {
                plugin.install.apply(plugin, args);
            } else {
                plugin.apply(null, args);
            }
            plugin.installed = true;
            return this;
        };

        /**
         * Apply a global mixin by merging it into the default
         * options.
         */

        Vue.mixin = function(mixin) {
            Vue.options = mergeOptions(Vue.options, mixin);
        };

        /**
         * Create asset registration methods with the following
         * signature:
         *
         * @param {String} id
         * @param {*} definition
         */

        config._assetTypes.forEach(function(type) {
            Vue[type] = function(id, definition) {
                if (!definition) {
                    return this.options[type + 's'][id];
                } else {
                    /* istanbul ignore if */
                    if ('development' !== 'production') {
                        if (type === 'component' && (commonTagRE.test(id) || reservedTagRE.test(id))) {
                            warn('Do not use built-in or reserved HTML elements as component ' + 'id: ' + id);
                        }
                    }
                    if (type === 'component' && isPlainObject(definition)) {
                        definition.name = id;
                        definition = Vue.extend(definition);
                    }
                    this.options[type + 's'][id] = definition;
                    return definition;
                }
            };
        });

        // expose internal transition API
        extend(Vue.transition, transition);
    }

    installGlobalAPI(Vue);

    Vue.version = '1.0.24';

    // devtools global hook
    /* istanbul ignore next */
    setTimeout(function() {
        if (config.devtools) {
            if (devtools) {
                devtools.emit('init', Vue);
            } else if ('development' !== 'production' && inBrowser && /Chrome\/\d+/.test(window.navigator.userAgent)) {
                console.log('Download the Vue Devtools for a better development experience:\n' + 'https://github.com/vuejs/vue-devtools');
            }
        }
    }, 0);

    return Vue;

}));