All files / ima/event EventBusImpl.js

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// @client-side
 
import ns from '../namespace';
import EventBus from './EventBus';
import GenericError from '../error/GenericError';
import Window from '../window/Window';
 
ns.namespace('ima.event');
 
/**
 * Global name of IMA.js custom event.
 *
 * @const
 * @type {string}
 */
export const IMA_EVENT = '$IMA.CustomEvent';
 
/**
 * Helper for custom events.
 *
 * It offers public methods for firing custom events and two methods for
 * catching events (e.g. inside view components).
 */
export default class EventBusImpl extends EventBus {
  static get $dependencies() {
    return [Window];
  }
 
  /**
	 * Initializes the custom event helper.
	 *
	 * @param {Window} window The IMA window helper.
	 */
  constructor(window) {
    super();
 
    /**
		 * The IMA window helper.
		 *
		 * @type {Window}
		 */
    this._window = window;
 
    /**
		 * Map of listeners provided to the public API of this event bus to a
		 * map of event targets to a map of event names to actual listeners
		 * bound to the native API.
		 *
		 * The "listen all" event listeners are not registered in this map.
		 *
		 * @type {WeakMap<
		 *         function(Event),
		 *         WeakMap<EventTarget, Map<string, function(Event)>>
		 *       >}
		 */
    this._listeners = new WeakMap();
 
    /**
		 * Map of event targets to listeners executed on all IMA.js event bus
		 * events.
		 *
		 * @type {WeakMap<EventTarget, WeakSet<function(Event)>>}
		 */
    this._allEventListeners = new WeakMap();
  }
 
  /**
	 * @inheritdoc
	 */
  fire(eventTarget, eventName, data, options = {}) {
    var eventInitialization = {};
    var params = { detail: { eventName, data } };
    var defaultOptions = { bubbles: true, cancelable: true };
    Object.assign(eventInitialization, defaultOptions, options, params);
 
    var event = this._window.createCustomEvent(IMA_EVENT, eventInitialization);
 
    if (eventTarget && typeof eventTarget.dispatchEvent !== 'undefined') {
      eventTarget.dispatchEvent(event);
    } else {
      throw new GenericError(
        `ima.event.EventBusImpl.fire: The EventSource ` +
          `${eventTarget} is not defined or can not dispatch event ` +
          `'${eventName}' (data: ${data}).`,
        { eventTarget, eventName, data, eventInitialization }
      );
    }
 
    return this;
  }
 
  /**
	 * @inheritdoc
	 */
  listenAll(eventTarget, listener) {
    this._window.bindEventListener(eventTarget, IMA_EVENT, listener);
 
    if (!this._allEventListeners.has(eventTarget)) {
      this._allEventListeners.set(eventTarget, new WeakSet());
    }
    this._allEventListeners.get(eventTarget).add(listener);
 
    return this;
  }
 
  /**
	 * @inheritdoc
	 */
  listen(eventTarget, eventName, listener) {
    Eif (!this._listeners.has(listener)) {
      this._listeners.set(listener, new WeakMap());
    }
 
    var targetToEventName = this._listeners.get(listener);
    Eif (!targetToEventName.has(eventTarget)) {
      targetToEventName.set(eventTarget, new Map());
    }
 
    var eventNameToNativeListener = targetToEventName.get(eventTarget);
    var nativeListener = event => {
      if (event.detail.eventName === eventName) {
        listener(event);
      }
    };
    eventNameToNativeListener.set(eventName, nativeListener);
 
    this._window.bindEventListener(eventTarget, IMA_EVENT, nativeListener);
 
    return this;
  }
 
  /**
	 * @inheritdoc
	 */
  unlistenAll(eventTarget, listener) {
    this._window.unbindEventListener(eventTarget, IMA_EVENT, listener);
 
    var listenerRegistered =
      this._allEventListeners.has(eventTarget) &&
      this._allEventListeners.get(eventTarget).has(listener);
    Eif (listenerRegistered) {
      this._allEventListeners.get(eventTarget).delete(listener);
    }
 
    Eif ($Debug) {
      Iif (!listenerRegistered) {
        console.warn(
          'The provided listener is not registered on the ' +
            'specified event target'
        );
      }
    }
 
    return this;
  }
 
  /**
	 * @inheritdoc
	 */
  unlisten(eventTarget, eventName, listener) {
    Iif (!this._listeners.has(listener)) {
      if ($Debug) {
        console.warn(
          'The provided listener is not bound to listen for the ' +
            'specified event on the specified event target.'
        );
      }
 
      return this;
    }
 
    var targets = this._listeners.get(listener);
    Iif (!targets.has(eventTarget)) {
      if ($Debug) {
        console.warn(
          'The provided listener is not bound to listen for the ' +
            'specified event on the specified event target.'
        );
      }
 
      return this;
    }
 
    var eventNameToNativeListener = targets.get(eventTarget);
    Iif (!eventNameToNativeListener.has(eventName)) {
      if ($Debug) {
        console.warn(
          'The provided listener is not bound to listen for the ' +
            'specified event on the specified event target.'
        );
      }
 
      return this;
    }
 
    var nativeListener = eventNameToNativeListener.get(eventName);
    this._window.unbindEventListener(eventTarget, IMA_EVENT, nativeListener);
 
    eventNameToNativeListener.delete(eventName);
    Iif (eventNameToNativeListener.size) {
      return this;
    }
 
    targets.delete(eventTarget);
 
    return this;
  }
}
 
ns.ima.event.EventBusImpl = EventBusImpl;