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Clients.claim

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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 possibly 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

Specification Status Comment
Service Workers
The definition of 'claim()' in that specification.
Working Draft Initial definition.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 42 ? 44
44
Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
No 29 No
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 42 42 ? 44 29 No 4.0

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/Clients/claim