The ServiceWorkerGlobalScope.onpushsubscriptionchange event of the ServiceWorkerGlobalScope interface is fired whenever a push subscription has been invalidated (or is about to become so). This offers an opportunity to resubscribe in order to continue receiving push messages, if desired. This might happen if, for example, the push service sets an expiration time a subscription.
The ServiceWorkerMessageEvent interface of the ServiceWorker API contains information about an event sent to a ServiceWorkerContainer target. This extends the default message event to allow setting a ServiceWorker object as the source of a message. The event object is accessed via the handler function of a message event, when fired by a message received from a service worker.
The pushManager property of the ServiceWorkerRegistration interface returns a reference to the PushManager interface for managing push subscriptions; this includes support for subscribing, getting an active subscription, and accessing push permission status.