/**
 * This class will notify all listeners any time any event get's fired.
 * @example
 *  let dispatcher = new Dispatcher();
 *  dispatcher.subscribe(callback);
 *  dispatcher.dispatch({ type : 'myEvent', payload : 'hello' });
 *
 * @class Dispatcher
 */
class Dispatcher {
  constructor() {
    this.listeners = [];
  }

  /**
   * Add a listener for all events
   * @param {function} callback
   */
  subscribe(callback) {
    this.listeners.push(callback);
  }

  /**
   * Remove a listener.
   * @param {function} callback
   */
  unsubscribe(callback) {
    this.listeners = this.listeners.filter(listener => listener !== callback);
  }

  /**
   * Dispatch an event to notify listeners.
   * @param {object} event - the event with a payload to emit
   */
  dispatch(event) {
    this.listeners.forEach((callback) => {
      callback(event);
    });
  }
}

export default Dispatcher;