PushManager：subscribe() 方法

subscribe(options)

this.onpush = (event) => {
  console.log(event.data);
  // From here we can write the data to IndexedDB, send it to any open
  // windows, display a notification, etc.
};

navigator.serviceWorker.register("serviceworker.js");

// Use serviceWorker.ready to ensure that you can subscribe for push
navigator.serviceWorker.ready.then((serviceWorkerRegistration) => {
  const options = {
    userVisibleOnly: true,
    applicationServerKey,
  };
  serviceWorkerRegistration.pushManager.subscribe(options).then(
    (pushSubscription) => {
      console.log(pushSubscription.endpoint);
      // The push subscription details needed by the application
      // server are now available, and can be sent to it using,
      // for example, the fetch() API.
    },
    (error) => {
      // During development it often helps to log errors to the
      // console. In a production environment it might make sense to
      // also report information about errors back to the
      // application server.
      console.error(error);
    },
  );
});

btn.addEventListener("click", () => {
  serviceWorkerRegistration.pushManager
    .subscribe(options)
    .then((pushSubscription) => {
      // handle subscription
    });
});