Clients

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 Clients interface provides access to Client objects. Access it via self.clients within a service worker.

Instance methods

Clients.get()

Returns a Promise for a Client matching a given id.

Clients.matchAll()

Returns a Promise for an array of Client objects. An options argument allows you to control the types of clients returned.

Clients.openWindow()

Opens a new browser window for a given URL and returns a Promise for the new WindowClient.

Clients.claim()

Allows an active service worker to set itself as the controller for all clients within its scope.

Examples

The following example shows an existing chat window or creates a new one when the user clicks a notification.

js
addEventListener("notificationclick", (event) => {
  event.waitUntil(
    (async () => {
      const allClients = await clients.matchAll({
        includeUncontrolled: true,
      });

      let chatClient;

      // Let's see if we already have a chat window open:
      for (const client of allClients) {
        const url = new URL(client.url);

        if (url.pathname === "/chat/") {
          // Excellent, let's use it!
          client.focus();
          chatClient = client;
          break;
        }
      }

      // If we didn't find an existing chat window,
      // open a new one:
      if (!chatClient) {
        chatClient = await clients.openWindow("/chat/");
      }

      // Message the client:
      chatClient.postMessage("New chat messages!");
    })(),
  );
});

Specifications

Specification
Service Workers
# clients-interface

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Clients
claim
get
matchAll
options.includeUncontrolled parameter
openWindow

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Partial support
Partial support
No support
No support
See implementation notes.
Has more compatibility info.

See also