index.js

const [waitingServiceWorker, setWaitingServiceWorker] = useState(null);
const [isUpdateAvailable, setUpdateAvailable] = useState(false);

React.useEffect(() => {
  serviceWorker.register({
    onUpdate: registration => {
      setWaitingServiceWorker(registration.waiting);
      setUpdateAvailable(true);
    }
  });
}, []);