digest.js

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

function digestMD5(content) {
    var md5sum = crypto.createHash('md5')
    md5sum.update(content)
    return md5sum.digest('hex')
}

function digestSHA1(content) {
    var sha1sum = crypto.createHash('sha1')
    sha1sum.update(content)
    return sha1sum.digest('hex')
}

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

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

            var hashNew = digestMD5(contents)
            if (
                !(filesHashes[file] && hashNew && filesHashes[file] === hashNew)
            ) {
                changed.push(file)
            }
            fileDone()
        })
    }

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

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

module.exports = {
    digestSHA1: digestSHA1,
    digestMD5: digestMD5,
    hasAnyFileChanged: hasAnyFileChanged,
}