Web/API/ServiceWorkerRegistration/update

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.

Note: This feature is available in Web Workers.

Syntax

serviceWorkerRegistration.update();

Parameters

None.

Return value

A Promise that resolves with a ServiceWorkerRegistration object.

Example

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-test/sw.js', {scope: 'sw-test'}).then(function(registration) {
    // registration worked
    console.log('Registration succeeded.');
    button.onclick = function() {
      registration.update();
    }
  }).catch(function(error) {
    // registration failed
    console.log('Registration failed with ' + error);
  });
};

Specifications

Specification	Status	Comment
Service WorkersThe definition of 'ServiceWorkerRegistration.update()' in that specification.	Working Draft	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`update` Experimental'	Chrome Full support 45 Notes' Full support 45 Notes' Notes' 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. Notes' 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 17 Full support 17 Full support 16 Disabled' Disabled' From version 16: this feature is behind the `Enable service workers` preference.	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 32 Notes' Full support 32 Notes' Notes' 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. Notes' 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 11.1	WebView Android Full support 45 Notes' Full support 45 Notes' Notes' 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. Notes' 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.	Chrome Android Full support 45 Notes' Full support 45 Notes' Notes' 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. Notes' 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.	Firefox Android Full support 44	Opera Android Full support 32 Notes' Full support 32 Notes' Notes' 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. Notes' 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 iOS No support No	Samsung Internet Android Full support 4.0 Notes' Full support 4.0 Notes' Notes' 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. Notes' 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.

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.