The pushsubscriptionchange event is sent to the global scope of a ServiceWorker to indicate a change in push subscription that was triggered outside the application's control.

This may occur if the subscription was refreshed by the browser, but it may also happen if the subscription has been revoked or lost.

This event is not cancelable and does not bubble.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("pushsubscriptionchange", (event) => {});

onpushsubscriptionchange = (event) => {};

A generic Event.

Although examples demonstrating how to share subscription related information with the application server tend to use fetch(), this is not necessarily the best choice for real-world use, since it will not work if the app is offline, for example.

Consider using another method to synchronize subscription information between your service worker and the app server, or make sure your code using fetch() is robust enough to handle cases where attempts to exchange data fail.

This example, run in the context of a service worker, listens for a pushsubscriptionchange event and re-subscribes to the lapsed subscription.

self.addEventListener(
  "pushsubscriptionchange",
  (event) => {
    const subscription = swRegistration.pushManager
      .subscribe(event.oldSubscription.options)
      .then((subscription) =>
        fetch("register", {
          method: "post",
          headers: {
            "Content-type": "application/json",
          },
          body: JSON.stringify({
            endpoint: subscription.endpoint,
          }),
        }),
      );
    event.waitUntil(subscription);
  },
  false,
);

When a pushsubscriptionchange event arrives, indicating that the subscription has expired, we resubscribe by calling the push manager's subscribe() method. When the returned promise is resolved, we receive the new subscription. This is delivered to the app server using a fetch() call to post a JSON formatted rendition of the subscription's endpoint to the app server.

You can also use the onpushsubscriptionchange event handler property to set up the event handler:

self.onpushsubscriptionchange = (event) => {
  event.waitUntil(
    swRegistration.pushManager
      .subscribe(event.oldSubscription.options)
      .then((subscription) => {
        /* ... */
      }),
  );
};

• Using the Push API