Clients: claim() method

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

The claim() method of the {{domxref("Clients")}}  interface allows an active service worker to set itself as the {{domxref("ServiceWorkerContainer.controller", "controller")}}  for all clients within its {{domxref("ServiceWorkerRegistration.scope", "scope")}} . This triggers a controllerchange event on {{domxref("ServiceWorkerContainer","navigator.serviceWorker")}}  in any clients that become controlled by this service worker.

When a service worker is initially registered, pages won’t use it until they next load. The claim() method causes those pages to be controlled immediately. Be aware that this results in your service worker controlling pages that loaded regularly over the network, or possibly via a different service worker.

Syntax

claim()

Parameters

None.

Return value

A {{jsxref("Promise")}}  that resolves to undefined.

Examples

The following example uses claim() inside service worker’s activate event listener so that clients loaded in the same scope do not need to be reloaded before their fetches will go through this service worker.

self.addEventListener("activate", (event) => {
  event.waitUntil(clients.claim());
});

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• Using Service Workers
• The service worker lifecycle
• {{domxref("ServiceWorkerGlobalScope.skipWaiting()", "self.skipWaiting()")}}  - skip the service worker’s waiting phase