updates.available.subscribe(event => {
     if (prompt('Update available for this app. Do you want to update it?')) {
         updates.activateUpdate().then(() => document.location.reload());
     }
 });

 interval(6 * 60 * 60).subscribe(() => updates.checkForUpdate());

 interval(10000).subscribe(() => updates.checkForUpdate());

 everySixHoursOnceAppIsStable$.subscribe(() => updates.checkForUpdate());

 updates.available.subscribe(event => {
   if (promptUser(event)) {
     updates.activateUpdate().then(() => document.location.reload());
   }
 });

 check_now()
 {
   this.updates.checkForUpdate();
 }