mtime.js

var fs = require('fs')
var async = require('async')

function getFilesMtimes(files, concurrencyLimit, done) {
    var filesMtimes = {}
    async.eachLimit(
        files,
        concurrencyLimit,
        function (file, fileDone) {
            fs.stat(file, function (statErr, stat) {
                if (statErr) {
                    if (statErr.code === 'ENOENT') return fileDone()
                    return fileDone(statErr)
                }

                filesMtimes[file] = stat.mtime.getTime()
                fileDone()
            })
        },
        function (err) {
            if (err) return done(err)
            done(null, filesMtimes)
        }
    )
}

function getFilesChanges(filesMtimes, concurrencyLimit, done) {
    var changed = []
    var deleted = []
    var files = Object.keys(filesMtimes)

    function eachFile(file, fileDone) {
        fs.stat(file, function (err, stat) {
            if (err) {
                deleted.push(file)
                return fileDone()
            }

            var mtimeNew = stat.mtime.getTime()
            if (mtimeNew > Number(filesMtimes[file])) {
                changed.push(file)
            }
            fileDone()
        })
    }

    async.eachLimit(files, concurrencyLimit, eachFile, function () {
        done(deleted, changed)
    })
}

function hasAnyFileChanged(filesMtimes, concurrencyLimit, done) {
    getFilesChanges(filesMtimes, concurrencyLimit, function (deleted, changed) {
        var numFilesChanged = deleted.length + changed.length
        done(null, numFilesChanged > 0)
    })
}

module.exports = {
    getFilesMtimes: getFilesMtimes,
    hasAnyFileChanged: hasAnyFileChanged,
}