text: /**
   * Copyright 2018 Google Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  importScripts('https://storage.googleapis.com/workbox-cdn/releases/3.4.1/workbox-sw.js');
  
  workbox.precaching.precacheAndRoute([]);
  
  workbox.routing.registerRoute(/\.(?:html|css)$/,
    workbox.strategies.cacheFirst({
      cacheName: 'pages',
    })
  );
  
  workbox.routing.registerRoute(/\.(?:png|gif|jpg)$/,
    workbox.strategies.cacheFirst({
      cacheName: 'images',
      plugins: [
        new workbox.expiration.Plugin({
          maxEntries: 50
        })
      ]
    })
  );
  