title: How to register multiple service worker in angular 6?
body: <p>I have converted my Angular 6 application into Progressive Web Apps, by registering the service worker in app.module .ts but also i am registering one more service worker for firebase push notification but i am unable to do that, where and how to register it?</p>
  
  <p>I have tried one solution by referring following link : 
  <a href="https://angularfirebase.com/snippets/how-to-use-a-firebase-fcm-service-worker-with-angular-s-ngsw-service-worker/" rel="nofollow noreferrer">https://angularfirebase.com/snippets/how-to-use-a-firebase-fcm-service-worker-with-angular-s-ngsw-service-worker/</a></p>
  
  <p>1 In file :  app.module.ts I have register service worker like this :</p>
  
  <p>ServiceWorkerModule.register('/ngsw-worker.js', { enabled: environment.production }),
          ServiceWorkerModule.register('/firebase-messaging-sw.js', { enabled: environment.production }),</p>
  
  <ol start="2">
  <li>In index.html wrote firebase push notification code.</li>
  <li><p>In angular.json invoked js files : </p>
  
  <pre><code>  "assets": [
        "src/favicon.ico",
        "src/assets",
        "src/firebase-messaging-sw.js",
        "src/manifest.webmanifest"
      ],
  </code></pre></li>
  </ol>
  
  <p>In console->application </p>
  
  <p>showing only one service worker registered i.e
  firebase-messaging-sw.js .</p>