ServiceWorkerGlobalScope: activate event

{{APIRef("Service Workers API")}}{{SecureContext_Header}}{{AvailableInWorkers("service")}}

The activate event of the {{domxref("ServiceWorkerGlobalScope")}} interface is fired when a {{domxref("ServiceWorkerRegistration")}} acquires a new {{domxref("ServiceWorkerRegistration.active")}} worker.

This event is not cancelable and does not bubble.

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.

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

onactivate = (event) => { }

Event type

An {{domxref("ExtendableEvent")}}. Inherits from {{domxref("Event")}}.

{{InheritanceDiagram("ExtendableEvent")}}

Event properties

Doesn't implement any specific properties, but inherits properties from its parent, {{domxref("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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("ServiceWorkerGlobalScope/install_event", "install")}} event
• {{domxref("ServiceWorkerGlobalScope")}}
• Service Worker API