Service worker registration failed -- PWA Not working after Universal Prerendering implementation in Angular 9

Question

Error Throwing in the console Log The script has an unsupported MIME type ('text/html').

Service worker registration failed with: DOMException: Failed to register a ServiceWorker for scope ('https://localhost:4000/') with script ('https://localhost:4000/ngsw-worker.js'): The script has an unsupported MIME type ('text/html').

Answer 1

Try

ServiceWorkerModule.register('ngsw-worker.js', { enabled: environment.production, scope: './', registrationStrategy: 'registerImmediately' })

inside app.module.ts

Answer 2

In my case service worker was twice registered.

Once from index.html

  <script type="text/javascript">

if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('/serviceworker').then(function (registration) {
    console.log('ServiceWorker registration successful with scope: ', registration.scope);
  }, function (err) {
    console.log('ServiceWorker registration failed: ', err);
  });
}

Second time by

ServiceWorkerModule.register('ngsw-worker.js', { enabled: environment.production })

inside app.module.ts

//ServiceWorkerModule.register('ngsw-worker.js', { enabled: environment.production })

Solved my problem.