module.exports = FSNotifier; var Promise = require('bluebird'); var fs = Promise.promisifyAll(require('fs')); var util = require('util'); function FSNotifier(options) { this._filename = options.filename; } FSNotifier.prototype.notify = function(identity, subject, link) { var content = util.format('User: %s\nSubject: %s\nLink: %s', identity.userid, subject, link); return fs.writeFileAsync(this._filename, content); }