Method forwardEvents

src/base-element.js:751–759

* Utility method that forwards the given list of non-bubbling events * from the given element to this element as custom events with the same name. * @param {string|!Array } events * @param {!Element} element * @public @final * @return {!UnlistenDef}

(events, element)

   * @return {!UnlistenDef}
   */
  forwardEvents(events, element) {
    const unlisteners = (isArray(events) ? events : [events]).map((eventType) =>
      listen(element, eventType, (event) => {
        dispatchCustomEvent(this.element, eventType, getData(event) || {});
      })
    );

    return () => unlisteners.forEach((unlisten) => unlisten());
  }

  /**
   * Returns an optional placeholder element for this custom element.