ServiceWorkerContainer.ready

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

The ready read-only property of the ServiceWorkerContainer interface provides a way of delaying code execution until a service worker is active. It returns a Promise that will never reject, and which waits indefinitely until the ServiceWorkerRegistration associated with the current page has an active worker. Once that condition is met, it resolves with the ServiceWorkerRegistration.

Syntax

navigator.serviceWorker.ready.then(function(serviceWorkerRegistration) { ... });

Value

A Promise that will never reject, and which may eventually resolve with a ServiceWorkerRegistration.

Example

if ('serviceWorker' in navigator) {
  navigator.serviceWorker.ready
  .then(function(registration) {
    console.log('A service worker is active:', registration.active);

    // At this point, you can call methods that require an active
    // service worker, like registration.pushManager.subscribe()
  });
} else {
  console.log('Service workers are not supported.');
}

Specifications

 
Specification Status Comment
Service Workers
The definition of 'ServiceWorkerRegistration.ready' in that specification.
Working Draft Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Experimental
Chrome Full support 40Edge 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 Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Edge Mobile ? Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support 11.1Samsung Internet Android Full support 4.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
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.

Document Tags and Contributors

Last updated by: slokhorst,