const events = require('events'); class EventManager { constructor() { this.emitter_ = new events.EventEmitter(); } on(eventName, callback) { return this.emitter_.on(eventName, callback); } emit(eventName, object = null) { return this.emitter_.emit(eventName, object); } removeListener(eventName, callback) { return this.emitter_.removeListener(eventName, callback); } off(eventName, callback) { return this.removeListener(eventName, callback); } } const eventManager = new EventManager(); module.exports = eventManager;