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ServiceWorkerRegistration

The ServiceWorkerRegistration interface of the Service Worker API represents the service worker registration. You register a service worker to control one or more pages that share the same origin.

The lifetime of a service worker registration is beyond that of the ServiceWorkerRegistration objects that represent them within the lifetime of their corresponding service worker clients. The browser maintains a persistent list of active ServiceWorkerRegistration objects.

Note: This feature is available in Web Workers.

Instance properties

Also implements properties from its parent interface, EventTarget.

ServiceWorkerRegistration.active Read only: Returns a service worker whose state is activating or activated. This is initially set to null. An active worker will control a Client if the client's URL falls within the scope of the registration (the scope option set when ServiceWorkerContainer.register is first called.)
ServiceWorkerRegistration.backgroundFetch Read only Experimental: Returns a reference to a BackgroundFetchManager object, which manages background fetch operations.
ServiceWorkerRegistration.index Read only Experimental: Returns a reference to the ContentIndex interface, for managing indexed content for offline viewing.
ServiceWorkerRegistration.installing Read only: Returns a service worker whose state is installing. This is initially set to null.
ServiceWorkerRegistration.navigationPreload Read only: Returns the instance of NavigationPreloadManager associated with the current service worker registration.
ServiceWorkerRegistration.paymentManager Experimental: Returns a payment app's PaymentManager instance, which is used to manage various payment app functionality.
ServiceWorkerRegistration.pushManager Read only: Returns a reference to the PushManager interface for managing push subscriptions including subscribing, getting an active subscription, and accessing push permission status.
ServiceWorkerRegistration.scope Read only: Returns a unique identifier for a service worker registration. This must be on the same origin as the document that registers the ServiceWorker.
ServiceWorkerRegistration.sync Read only Experimental: Returns a reference to the SyncManager interface, which manages background synchronization processes.
ServiceWorkerRegistration.waiting Read only: Returns a service worker whose state is installed. This is initially set to null.
ServiceWorkerRegistration.updateViaCache Read only: Returns a string indicating what is the cache strategy to use when updating the service worker scripts. It can be one of the following: imports, all, or none.

Instance methods

Also implements methods from its parent interface, EventTarget.

ServiceWorkerRegistration.getNotifications(): Returns a Promise that resolves to an array of Notification objects.
ServiceWorkerRegistration.showNotification(): Displays the notification with the requested title.
ServiceWorkerRegistration.unregister(): Unregisters the service worker registration and returns a Promise. The service worker will finish any ongoing operations before it is unregistered.
ServiceWorkerRegistration.update(): Checks the server for an updated version of the service worker without consulting caches.

Events

updatefound: Fired any time the ServiceWorkerRegistration.installing property acquires a new service worker.

Examples

In this example, the code first checks whether the browser supports service workers and if so registers one. Next, it adds an updatefound listener in which it uses the service worker registration to listen for further changes to the service worker's state. If the service worker hasn't changed since the last time it was registered, then the updatefound event will not be fired.

if ("serviceWorker" in navigator) {
  navigator.serviceWorker
    .register("/sw.js")
    .then((registration) => {
      registration.addEventListener("updatefound", () => {
        // If updatefound is fired, it means that there's
        // a new service worker being installed.
        const installingWorker = registration.installing;
        console.log(
          "A new service worker is being installed:",
          installingWorker,
        );

        // You can listen for changes to the installing service worker's
        // state via installingWorker.onstatechange
      });
    })
    .catch((error) => {
      console.error(`Service worker registration failed: ${error}`);
    });
} else {
  console.error("Service workers are not supported.");
}

Specifications

Specification
Service Workers # serviceworkerregistration-interface
Push API # extensions-to-the-serviceworkerregistration-interface

Browser compatibility