Method onDestroy

packages/core/src/application/application_ref.ts:786–790

* Registers a listener to be called when an instance is destroyed. * * @param callback A callback function to add as a listener. * @returns A function which unregisters a listener.

(callback: () => void)

   * @returns A function which unregisters a listener.
   */
  onDestroy(callback: () => void): VoidFunction {
    (typeof ngDevMode === 'undefined' || ngDevMode) && warnIfDestroyed(this._destroyed);
    this._destroyListeners.push(callback);
    return () => remove(this._destroyListeners, callback);
  }

  /**
   * Destroys an Angular application represented by this `ApplicationRef`. Calling this function