Firefox Tomorrow

web api event

ServiceWorkerGlobalScope: activate event

View on MDN ↗

Secure contextAvailable in workers

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

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

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also