text: importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-app.js');
  importScripts('https://www.gstatic.com/firebasejs/3.9.0/firebase-messaging.js');
  
  firebase.initializeApp({
      'messagingSenderId': 'myId'
  });
  
  const messaging = firebase.messaging();