ServiceWorkerGlobalScope: activate event

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is only available in Service Workers.

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.

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

onactivate = (event) => {};

Event type

An ExtendableEvent. Inherits from Event.

Event ExtendableEvent

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.

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

  event.waitUntil(
    caches.forEach((cache, cacheName) => {
      if (!cacheAllowlist.includes(cacheName)) {
        return caches.delete(cacheName);
      }
    }),
  );
});

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

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

Specifications

Specification
Service Workers
# service-worker-global-scope-activate-event
Service Workers
# dom-serviceworkerglobalscope-onactivate

Browser compatibility

BCD tables only load in the browser

See also