Method updateController

packages/service-worker/src/low_level.ts:166–173

()

        return workerSubject.subscribe((v) => subscriber.next(v));
      });
      const updateController = () => {
        const {controller} = serviceWorker;
        if (controller === null) {
          return;
        }
        currentWorker = controller;
        workerSubject.next(currentWorker);
      };
      serviceWorker.addEventListener('controllerchange', updateController);
      updateController();