Manifest V3 module service worker demo

background.js

// Copyright 2021 Google LLC
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

// Use importScripts to load other JS files
import { demo } from './lib.js';

console.log(demo.greeting);

/*
 * Uncomment this block and reload the extension to see how errors are handled.
 * When enabled in Canary (as of 2021-07-23), the extension's error page will
 * contain two entries:
 *
 * - A warning stating "Service worker registration failed"
 * - An error stating "Uncaught Error: Testing error handling"
 */

// throw new Error('Testing error handling');

lib.js

// Copyright 2021 Google LLC
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

export const demo = {
  greeting: 'Hello, world!'
}

manifest.json

{
  "name": "Module service worker demo",
  "version": "1.0",
  "manifest_version": 3,
  "background": {
    "service_worker": "background.js",
    "type": "module"
  }
}