Clients: claim() method

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.

Note: This feature is only available in Service Workers.

The claim() method of the Clients interface 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 possibly via a different service worker.

Syntax

js
claim()

Parameters

None.

Return value

A 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.

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

Specifications

Specification
Service Workers
# clients-claim

Browser compatibility

BCD tables only load in the browser

See also