Method off

src/Observable.ts:138–160

(
    arg0?: K | EventRegistryObject<EventSpec>,
    handler?: TEventCallback
  )

   */
  off(): void;
  off<K extends keyof EventSpec>(
    arg0?: K | EventRegistryObject<EventSpec>,
    handler?: TEventCallback
  ) {
    if (!this.__eventListeners) {
      return;
    }

    // remove all key/value pairs (event name -> event handler)
    if (typeof arg0 === 'undefined') {
      for (const eventName in this.__eventListeners) {
        this._removeEventListener(eventName);
      }
    }
    // one object with key/value pairs was passed
    else if (typeof arg0 === 'object') {
      Object.entries(arg0).forEach(([eventName, handler]) => {
        this._removeEventListener(eventName as K, handler as TEventCallback);
      });
    } else {
      this._removeEventListener(arg0, handler);
    }
  }

  /**
   * Fires event with an optional options object