Retrieves an existing push subscription.
Retrieves an existing push subscription. It returns a Promise that resolves to a PushSubscription object containing details of an existing subscription. If no existing subscription exists, this resolves to a null value.
MDN
The permissionState() method of the PushManager interface returns a Promise that resolves to a DOMString indicating the permission state of the push manager.
The permissionState() method of the PushManager interface returns a Promise that resolves to a DOMString indicating the permission state of the push manager. Possible values are 'prompt', 'denied', or 'granted'.
An object containing optional configuration parameters. It can have the following properties: - userVisibleOnly: A boolean indicating that the returned push subscription will only be used for messages whose effect is made visible to the user. MDN
The subscribe() method of the PushManager interface subscribes to a push service.
The subscribe() method of the PushManager interface subscribes to a push service.
It returns a Promise that resolves to a PushSubscription object containing details of a push subscription. A new push subscription is created if the current service worker does not have an existing subscription.
MDN
The PushManager interface of the Push API provides a way to receive notifications from third-party servers as well as request URLs for push notifications.
This interface is accessed via the ServiceWorkerRegistration.pushManager property.
MDN
The Push API is currently specified here: http://www.w3.org/TR/2015/WD-push-api-20151215/