app.js

Notification.requestPermission(result => {
  if (result === 'granted') {
    showNotification('So nice to have you here!', 'Hey there!')
  }
});

function showNotification(title, message) {
  if ('Notification' in window) {
    navigator.serviceWorker.ready.then(registration => {
      registration.showNotification(title, {
        body: message,
        tag: 'vibration-sample'
      });
    });
  }
}