hyperjson.js

/*
 * Copyright 2024 XWiki SAS
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
(function () {
    var Hyperjson = {};
    var isArray = function (A) {
        return Object.prototype.toString.call(A)==='[object Array]';
    };

    var isTruthy = function (x) {
        return x;
    };

    var callOnHyperJSON = Hyperjson.callOn = function (hj, cb) {
        var children;

        if (hj && hj[2]) {
            children = hj[2].map(function (child) {
                if (isArray(child)) {
                    // if the child is an array, recurse
                    return callOnHyperJSON(child, cb);
                } else if (typeof (child) === 'string') {
                    return child;
                } else {
                    // the above branches should cover all methods
                    // if we hit this, there is a problem
                    throw new Error();
                }
            });
        } else {
            children = [];
        }
        // this should return the top level element of your new DOM
        return cb(hj[0], hj[1], children);
    };

    var DOM2HyperJSON = Hyperjson.fromDOM = function(el, predicate, filter){
        if(!el.tagName && el.nodeType === Node.TEXT_NODE){
            return el.textContent;
        }
        if(!el.attributes){
          return;
        }
        if (predicate) {
            if (!predicate(el)) {
                // shortcircuit
                return;
            }
        }

        var attributes = {};

        var i = 0;
        for(;i < el.attributes.length; i++){
            var attr = el.attributes[i];
            if(attr.name && attr.value){
                attributes[attr.name] = attr.value;
            }
        }

        // this should never be longer than three elements
        var result = [];

        // get the element type, id, and classes of the element
        // and push them to the result array
        result.push(el.tagName);

        // second element of the array is the element attributes
        result.push(attributes);

        // third element of the array is an array of child nodes
        var children = [];

        // js hint complains if we use 'var' here
        i = 0;
        for(; i < el.childNodes.length; i++){
            children.push(DOM2HyperJSON(el.childNodes[i], predicate, filter));
        }
        result.push(children.filter(isTruthy));

        if (filter) {
            return filter(result);
        } else {
            return result;
        }
    };

    var H = Hyperjson.toDOM = function(hj) {
        if (typeof(hj) === 'string') { return document.createTextNode(hj); }
        var e = document.createElement(hj[0]);
        for (var x in hj[1]) { e.setAttribute(x, hj[1][x]); }
        for (var i = 0; i < hj[2].length; i++) { e.appendChild(H(hj[2][i])); }
        return e;
    };

    if (typeof(module) !== 'undefined' && module.exports) {
        module.exports = Hyperjson;
    } else if ((typeof(define) !== 'undefined' && define !== null) && (define.amd !== null)) {
        define(function () {
            return Hyperjson;
        });
    } else {
        window.Hyperjson = Hyperjson;
    }
}());