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