Method triggerEventHandler

packages/core/src/debug/debug_node.ts:355–389

* Triggers the event by its name if there is a corresponding listener in the element's * `listeners` collection. * * If the event lacks a listener or there's some other problem, consider * calling `nativeElement.dispatchEvent(eventObject)`. * * @param eventName The name of the even

(eventName: string, eventObj?: any)

   * @see [Testing components scenarios](guide/testing/components-scenarios#trigger-event-handler)
   */
  triggerEventHandler(eventName: string, eventObj?: any): void {
    const node = this.nativeNode as any;
    const invokedListeners: Function[] = [];

    this.listeners.forEach((listener) => {
      if (listener.name === eventName) {
        const callback = listener.callback;
        callback.call(node, eventObj);
        invokedListeners.push(callback);
      }
    });

    // We need to check whether `eventListeners` exists, because it's something
    // that Zone.js only adds to `EventTarget` in browser environments.
    if (typeof node.eventListeners === 'function') {
      // Note that in Ivy we wrap event listeners with a call to `event.preventDefault` in some
      // cases. We use '__ngUnwrap__' as a special token that gives us access to the actual event
      // listener.
      node.eventListeners(eventName).forEach((listener: Function) => {
        // In order to ensure that we can detect the special __ngUnwrap__ token described above, we
        // use `toString` on the listener and see if it contains the token. We use this approach to
        // ensure that it still worked with compiled code since it cannot remove or rename string
        // literals. We also considered using a special function name (i.e. if(listener.name ===
        // special)) but that was more cumbersome and we were also concerned the compiled code could
        // strip the name, turning the condition in to ("" === "") and always returning true.
        if (listener.toString().indexOf('__ngUnwrap__') !== -1) {
          const unwrappedListener = listener('__ngUnwrap__');
          return (
            invokedListeners.indexOf(unwrappedListener) === -1 &&
            unwrappedListener.call(node, eventObj)
          );
        }
      });
    }
  }
}

function copyDomProperties(element: Element | null, properties: {[name: string]: string}): void {