Method emit

src/tutorial/tutorialManager.js:164–168

* Emit event * @param {string} event - Event name * @param {*} data - Event data

(event, data)

   * @param {*} data - Event data
   */
  emit(event, data) {
    if (this.listeners.has(event)) {
      this.listeners.get(event).forEach(callback => callback(data));
    }
  }
}