ServiceWorkerGlobalScope: activate event

The activate event of the ServiceWorkerGlobalScope interface is fired when a ServiceWorkerRegistration acquires a new ServiceWorkerRegistration.active worker.

This event is not cancelable and does not bubble.

Syntax

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

addEventListener("activate", (event) => { })

onactivate = (event) => { }

Event type

An ExtendableEvent. Inherits from Event.

Event properties

Doesn't implement any specific properties, but inherits properties from its parent, Event.

Examples

The following snippet shows how you could use an activate event handler to upgrade a cache.

self.addEventListener("activate", (event) => {
  const cacheAllowlist = ["v2"];

  event.waitUntil(
    caches.keys().then((cacheNames) =>
      Promise.all(
        cacheNames.map((cacheName) => {
          if (!cacheAllowlist.includes(cacheName)) {
            return caches.delete(cacheName);
          }
          return undefined;
        }),
      ),
    ),
  );
});

You can also set up the event handler using the onactivate property:

self.onactivate = (event) => {
  // …
};

Specifications

Browser compatibility

See also

• install event
• ServiceWorkerGlobalScope
• Service Worker API