var fs = require('fs')
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var path = require('path')
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var util = require('util')
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function Y18N (opts) {
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// configurable options.
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opts = opts || {}
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this.directory = opts.directory || './locales'
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this.updateFiles = typeof opts.updateFiles === 'boolean' ? opts.updateFiles : true
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this.locale = opts.locale || 'en'
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this.fallbackToLanguage = typeof opts.fallbackToLanguage === 'boolean' ? opts.fallbackToLanguage : true
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// internal stuff.
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this.cache = Object.create(null)
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this.writeQueue = []
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}
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Y18N.prototype.__ = function () {
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if (typeof arguments[0] !== 'string') {
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return this._taggedLiteral.apply(this, arguments)
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}
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var args = Array.prototype.slice.call(arguments)
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var str = args.shift()
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var cb = function () {} // start with noop.
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if (typeof args[args.length - 1] === 'function') cb = args.pop()
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cb = cb || function () {} // noop.
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if (!this.cache[this.locale]) this._readLocaleFile()
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// we've observed a new string, update the language file.
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if (!this.cache[this.locale][str] && this.updateFiles) {
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this.cache[this.locale][str] = str
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// include the current directory and locale,
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// since these values could change before the
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// write is performed.
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this._enqueueWrite([this.directory, this.locale, cb])
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} else {
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cb()
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}
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return util.format.apply(util, [this.cache[this.locale][str] || str].concat(args))
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}
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Y18N.prototype._taggedLiteral = function (parts) {
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var args = arguments
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var str = ''
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parts.forEach(function (part, i) {
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var arg = args[i + 1]
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str += part
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if (typeof arg !== 'undefined') {
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str += '%s'
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}
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})
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return this.__.apply(null, [str].concat([].slice.call(arguments, 1)))
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}
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Y18N.prototype._enqueueWrite = function (work) {
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this.writeQueue.push(work)
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if (this.writeQueue.length === 1) this._processWriteQueue()
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}
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Y18N.prototype._processWriteQueue = function () {
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var _this = this
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var work = this.writeQueue[0]
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// destructure the enqueued work.
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var directory = work[0]
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var locale = work[1]
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var cb = work[2]
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var languageFile = this._resolveLocaleFile(directory, locale)
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var serializedLocale = JSON.stringify(this.cache[locale], null, 2)
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fs.writeFile(languageFile, serializedLocale, 'utf-8', function (err) {
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_this.writeQueue.shift()
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if (_this.writeQueue.length > 0) _this._processWriteQueue()
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cb(err)
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})
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}
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Y18N.prototype._readLocaleFile = function () {
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var localeLookup = {}
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var languageFile = this._resolveLocaleFile(this.directory, this.locale)
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try {
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localeLookup = JSON.parse(fs.readFileSync(languageFile, 'utf-8'))
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} catch (err) {
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if (err instanceof SyntaxError) {
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err.message = 'syntax error in ' + languageFile
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}
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if (err.code === 'ENOENT') localeLookup = {}
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else throw err
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}
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this.cache[this.locale] = localeLookup
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}
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Y18N.prototype._resolveLocaleFile = function (directory, locale) {
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var file = path.resolve(directory, './', locale + '.json')
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if (this.fallbackToLanguage && !this._fileExistsSync(file) && ~locale.lastIndexOf('_')) {
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// attempt fallback to language only
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var languageFile = path.resolve(directory, './', locale.split('_')[0] + '.json')
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if (this._fileExistsSync(languageFile)) file = languageFile
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}
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return file
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}
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// this only exists because fs.existsSync() "will be deprecated"
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// see https://nodejs.org/api/fs.html#fs_fs_existssync_path
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Y18N.prototype._fileExistsSync = function (file) {
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try {
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return fs.statSync(file).isFile()
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} catch (err) {
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return false
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}
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}
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Y18N.prototype.__n = function () {
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var args = Array.prototype.slice.call(arguments)
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var singular = args.shift()
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var plural = args.shift()
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var quantity = args.shift()
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var cb = function () {} // start with noop.
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if (typeof args[args.length - 1] === 'function') cb = args.pop()
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if (!this.cache[this.locale]) this._readLocaleFile()
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var str = quantity === 1 ? singular : plural
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if (this.cache[this.locale][singular]) {
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str = this.cache[this.locale][singular][quantity === 1 ? 'one' : 'other']
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}
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// we've observed a new string, update the language file.
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if (!this.cache[this.locale][singular] && this.updateFiles) {
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this.cache[this.locale][singular] = {
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one: singular,
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other: plural
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}
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// include the current directory and locale,
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// since these values could change before the
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// write is performed.
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this._enqueueWrite([this.directory, this.locale, cb])
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} else {
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cb()
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}
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// if a %d placeholder is provided, add quantity
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// to the arguments expanded by util.format.
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var values = [str]
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if (~str.indexOf('%d')) values.push(quantity)
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return util.format.apply(util, values.concat(args))
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}
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Y18N.prototype.setLocale = function (locale) {
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this.locale = locale
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}
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Y18N.prototype.getLocale = function () {
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return this.locale
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}
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Y18N.prototype.updateLocale = function (obj) {
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if (!this.cache[this.locale]) this._readLocaleFile()
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for (var key in obj) {
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this.cache[this.locale][key] = obj[key]
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}
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}
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module.exports = function (opts) {
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var y18n = new Y18N(opts)
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// bind all functions to y18n, so that
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// they can be used in isolation.
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for (var key in y18n) {
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if (typeof y18n[key] === 'function') {
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y18n[key] = y18n[key].bind(y18n)
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}
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}
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return y18n
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}
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