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 Workers
The definition of 'ServiceWorkerRegistration.update()' in that specification.
Working Draft Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung 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 NoOpera 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 11.1WebView 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 44Opera 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 NoSamsung 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.

See also