The matchAll() method of the Clients interface returns a Promise for a list of service worker clients. Include the options parameter to return all service worker clients whose origin is the same as the associated service worker's origin. If options are not included, the method returns only the service worker clients controlled by the service worker.
The Push API gives web applications the ability to receive messages pushed to them from a server, whether or not the web app is in the foreground, or even currently loaded, on a user agent. This lets developers deliver asynchronous notifications and updates to users that opt in, resulting in better engagement with timely new content.