ServiceWorkerRegistration.getNotifications()

The getNotifications() method of the ServiceWorkerRegistration interface returns a list of the notifications in the order that they were created from the current origin via the current service worker registration. Origins can have many active but differently-scoped service worker registrations. Notifications created by one service worker on the same origin will not be available to other active services workers on that same origin.

serviceWorkerRegistration.getNotifications(options)
.then(function(notificationsList) { ... });

options Optional

An object containing options to filter the notifications returned. The available options are:

• tag: A DOMString representing a notification tag. If specified, only notifications that have this tag will be returned.

A Promise that resolves to a list of Notification objects.

navigator.serviceWorker.register('sw.js');

var options = { tag : 'user_alerts' };

navigator.serviceWorker.ready.then(function(registration) {
  registration.getNotifications(options).then(function(notifications) {
    // do something with your notifications
  })
});