Feature request - service worker generator

[bovas85]

Following the google web developer starter kit for progressive webapps, can we add this to the options of the gulpfile?

// Copy over the scripts that are used in importScripts as part of the generate-service-worker task.
gulp.task('copy-sw-scripts', () => {
  return gulp.src(['node_modules/sw-toolbox/sw-toolbox.js', 'app/scripts/sw/runtime-caching.js'])
    .pipe(gulp.dest('dist/scripts/sw'));
});

// See http://www.html5rocks.com/en/tutorials/service-worker/introduction/ for
// an in-depth explanation of what service workers are and why you should care.
// Generate a service worker file that will provide offline functionality for
// local resources. This should only be done for the 'dist' directory, to allow
// live reload to work as expected when serving from the 'app' directory.
gulp.task('generate-service-worker', ['copy-sw-scripts'], () => {
  const rootDir = 'dist';
  const filepath = path.join(rootDir, 'service-worker.js');

  return swPrecache.write(filepath, {
    // Used to avoid cache conflicts when serving on localhost.
    cacheId: pkg.name || 'web-starter-kit',
    // sw-toolbox.js needs to be listed first. It sets up methods used in runtime-caching.js.
    importScripts: [
      'scripts/sw/sw-toolbox.js',
      'scripts/sw/runtime-caching.js'
    ],
    staticFileGlobs: [
      // Add/remove glob patterns to match your directory setup.
      `${rootDir}/images/**/*`,
      `${rootDir}/scripts/**/*.js`,
      `${rootDir}/styles/**/*.css`,
      `${rootDir}/*.{html,json}`
    ],
    // Translates a static file path to the relative URL that it's served from.
    // This is '/' rather than path.sep because the paths returned from
    // glob always use '/'.
    stripPrefix: rootDir + '/'
  });
});