ServiceWorkerRegistration: update() 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.

See full compatibility

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web Workers.

The update() method of the ServiceWorkerRegistration interface attempts to update the service worker. It fetches the worker's script URL, and if the new worker is not byte-by-byte identical to the current worker, it installs the new worker. The fetch of the worker bypasses any browser caches if the previous fetch occurred over 24 hours ago.

Syntax

update()

Parameters

None.

Return value

A Promise that resolves with a ServiceWorkerRegistration object.

Examples

The following simple example registers a service worker example then adds an event handler to a button so you can explicitly update the service worker whenever desired:

if ("serviceWorker" in navigator) {
  navigator.serviceWorker
    .register("/sw.js", { scope: "/" })
    .then((registration) => {
      // registration worked
      console.log("Registration succeeded.");
      button.onclick = () => {
        registration.update();
      };
    })
    .catch((error) => {
      // registration failed
      console.error(`Registration failed with ${error}`);
    });
}

Specifications

Specification
Service Workers Nightly # service-worker-registration-update

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`update`	Chrome – Full support Chrome 45 (Release date: 2015-09-01) footnote footnote Starting with Chrome 46, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before Chrome 48, this method always bypassed the browser cache. Starting with Chrome 48, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	Edge – Full support Edge 17 (Release date: 2018-04-30) footnote Full support	Firefox – Full support Firefox 44 (Release date: 2016-01-26) footnote Full support	Opera – Full support Opera 32 (Release date: 2015-09-15) footnote footnote Starting with Opera 33, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before Opera 35, this method always bypassed the browser cache. Starting with Opera 35, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	Safari – Full support Safari 11.1 (Release date: 2018-04-12) footnote Full support	Chrome Android – Full support Chrome Android 45 (Release date: 2015-09-01) footnote footnote Starting with Chrome Android 46, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before Chrome Android 48, this method always bypassed the browser cache. Starting with Chrome Android 48, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	Firefox for Android – Full support Firefox for Android 44 (Release date: 2016-01-26) footnote Full support	Opera Android – Full support Opera Android 32 (Release date: 2015-09-23) footnote footnote Starting with Opera Android 33, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before Opera Android 35, this method always bypassed the browser cache. Starting with Opera Android 35, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	Safari on iOS – Full support Safari on iOS 11.3 (Release date: 2018-03-29) footnote Full support	Samsung Internet – Full support Samsung Internet 4 (Release date: 2016-03-11) footnote footnote Starting with Samsung Internet 5.0, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before Samsung Internet 5.0, this method always bypassed the browser cache. Starting with Samsung Internet 5.0, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	WebView Android – Full support WebView Android 45 (Release date: 2015-09-01) footnote footnote Starting with WebView Android 46, update() returns a promise that resolves with 'undefined' if the operation completed successfully or there was no update, and rejects if update failed. If the new worker ran but installation failed, the promise still resolves. Formerly, it raised an exception. footnote Before WebView Android 48, this method always bypassed the browser cache. Starting with WebView Android 48, it only bypasses the cache when the previous service worker check was more than twenty-four hours ago.	WebView on iOS – No support WebView on iOS footnote No support

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Full support: Full support
No support: No support
: See implementation notes.