1/*
2 Copyright 2016 Google Inc. All Rights Reserved.
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6 http://www.apache.org/licenses/LICENSE-2.0
7 Unless required by applicable law or agreed to in writing, software
8 distributed under the License is distributed on an "AS IS" BASIS,
9 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
10 See the License for the specific language governing permissions and
11 limitations under the License.
12 */
13
14// Names of the two caches used in this version of the service worker.
15// Change to v2, etc. when you update any of the local resources, which will
16// in turn trigger the install event again.
17const PRECACHE = 'precache-v1';
18const RUNTIME = 'runtime';
19
20// A list of local resources we always want to be cached.
21const PRECACHE_URLS = [
22  'index.html',
23  './', // Alias for index.html
24  'styles.css',
25  '../../styles/main.css',
26  'demo.js'
27];
28
29// The install handler takes care of precaching the resources we always need.
30self.addEventListener('install', event => {
31  event.waitUntil(
32    caches.open(PRECACHE)
33      .then(cache => cache.addAll(PRECACHE_URLS))
34      .then(self.skipWaiting())
35  );
36});
37
38// The activate handler takes care of cleaning up old caches.
39self.addEventListener('activate', event => {
40  const currentCaches = [PRECACHE, RUNTIME];
41  event.waitUntil(
42    caches.keys().then(cacheNames => {
43      return cacheNames.filter(cacheName => !currentCaches.includes(cacheName));
44    }).then(cachesToDelete => {
45      return Promise.all(cachesToDelete.map(cacheToDelete => {
46        return caches.delete(cacheToDelete);
47      }));
48    }).then(() => self.clients.claim())
49  );
50});
51
52// The fetch handler serves responses for same-origin resources from a cache.
53// If no response is found, it populates the runtime cache with the response
54// from the network before returning it to the page.
55self.addEventListener('fetch', event => {
56  // Skip cross-origin requests, like those for Google Analytics.
57  if (event.request.url.startsWith(self.location.origin)) {
58    event.respondWith(
59      caches.match(event.request).then(cachedResponse => {
60        if (cachedResponse) {
61          return cachedResponse;
62        }
63
64        return caches.open(RUNTIME).then(cache => {
65          return fetch(event.request).then(response => {
66            // Put a copy of the response in the runtime cache.
67            return cache.put(event.request, response.clone()).then(() => {
68              return response;
69            });
70          });
71        });
72      })
73    );
74  }
75});

1if ('serviceWorker' in navigator) {  window.addEventListener('load', function() {    navigator.serviceWorker.register('/sw.js').then(function(registration) {      // Registration was successful      console.log('ServiceWorker registration successful with scope: ', registration.scope);    }, function(err) {      // registration failed :(      console.log('ServiceWorker registration failed: ', err);    });  });}