I use SwPush for handling push notifications in my Angular app. Here is the code:

export class AppComponent implements OnInit {
  constructor(private swPush: SwPush) { }

  ngOnInit(): void {
    this.initServiceWorker();
  }

  initServiceWorker(): any {
    if (environment.production) {
      if (this.swPush.isEnabled) {
        this.swPush.requestSubscription({
          serverPublicKey: environment.VAPID_PUBLIC_KEY
        })
        .then(sub => {
          // send subscription to server
          this.http.post(environment.apiUrl + 'pushnotifications/subscribe', sub).subscribe(response => {
            console.log(response);
          });
        })
        .catch(err => console.error('Could not subscribe to notifications', err));
      }
    }
  }
}

Currently, I store the Subscriptions in a database. The issue is, that on each page refresh I send a request to the backend, which verifies if the subscription already exists.

Question:

Is there a way to check if the user allows the Notifications yet or exists the permission already on the browser-side (by Angular)?