Clients.claim

The claim() method of the Clients allows an active service worker to set itself as the controller for all clients within its scope. This triggers a "controllerchange" event on 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 possible via a different service worker.

Syntax

await clients.claim();

Parameters

None.

Returns

A Promise for void.

Example

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

Browser compatibility

[1] Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)

See also

• Using Service Workers
• The service worker lifecycle
• Is ServiceWorker ready?
• Promises
• self.skipWaiting() - skip the service worker's waiting phase