66 | );
67 | }
68 | }
69 |
70 | export default App;
71 |
--------------------------------------------------------------------------------
/public/index.html:
--------------------------------------------------------------------------------
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
12 |
13 |
22 | React App
23 |
24 |
25 |
28 |
29 |
39 |
40 |
41 |
--------------------------------------------------------------------------------
/src/serviceWorker.js:
--------------------------------------------------------------------------------
1 | // In production, we register a service worker to serve assets from local cache.
2 |
3 | // This lets the app load faster on subsequent visits in production, and gives
4 | // it offline capabilities. However, it also means that developers (and users)
5 | // will only see deployed updates on the "N+1" visit to a page, since previously
6 | // cached resources are updated in the background.
7 |
8 | // To learn more about the benefits of this model, read https://goo.gl/KwvDNy.
9 | // This link also includes instructions on opting out of this behavior.
10 |
11 | const isLocalhost = Boolean(
12 | window.location.hostname === 'localhost' ||
13 | // [::1] is the IPv6 localhost address.
14 | window.location.hostname === '[::1]' ||
15 | // 127.0.0.1/8 is considered localhost for IPv4.
16 | window.location.hostname.match(
17 | /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
18 | )
19 | );
20 |
21 | export function register(config) {
22 | if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
23 | // The URL constructor is available in all browsers that support SW.
24 | const publicUrl = new URL(process.env.PUBLIC_URL, window.location);
25 | if (publicUrl.origin !== window.location.origin) {
26 | // Our service worker won't work if PUBLIC_URL is on a different origin
27 | // from what our page is served on. This might happen if a CDN is used to
28 | // serve assets; see https://github.com/facebook/create-react-app/issues/2374
29 | return;
30 | }
31 |
32 | window.addEventListener('load', () => {
33 | const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
34 |
35 | if (isLocalhost) {
36 | // This is running on localhost. Let's check if a service worker still exists or not.
37 | checkValidServiceWorker(swUrl, config);
38 |
39 | // Add some additional logging to localhost, pointing developers to the
40 | // service worker/PWA documentation.
41 | navigator.serviceWorker.ready.then(() => {
42 | console.log(
43 | 'This web app is being served cache-first by a service ' +
44 | 'worker. To learn more, visit https://goo.gl/SC7cgQ'
45 | );
46 | });
47 | } else {
48 | // Is not local host. Just register service worker
49 | registerValidSW(swUrl, config);
50 | }
51 | });
52 | }
53 | }
54 |
55 | function registerValidSW(swUrl, config) {
56 | navigator.serviceWorker
57 | .register(swUrl)
58 | .then(registration => {
59 | registration.onupdatefound = () => {
60 | const installingWorker = registration.installing;
61 | installingWorker.onstatechange = () => {
62 | if (installingWorker.state === 'installed') {
63 | if (navigator.serviceWorker.controller) {
64 | // At this point, the old content will have been purged and
65 | // the fresh content will have been added to the cache.
66 | // It's the perfect time to display a "New content is
67 | // available; please refresh." message in your web app.
68 | console.log('New content is available; please refresh.');
69 |
70 | // Execute callback
71 | if (config.onUpdate) {
72 | config.onUpdate(registration);
73 | }
74 | } else {
75 | // At this point, everything has been precached.
76 | // It's the perfect time to display a
77 | // "Content is cached for offline use." message.
78 | console.log('Content is cached for offline use.');
79 |
80 | // Execute callback
81 | if (config.onSuccess) {
82 | config.onSuccess(registration);
83 | }
84 | }
85 | }
86 | };
87 | };
88 | })
89 | .catch(error => {
90 | console.error('Error during service worker registration:', error);
91 | });
92 | }
93 |
94 | function checkValidServiceWorker(swUrl, config) {
95 | // Check if the service worker can be found. If it can't reload the page.
96 | fetch(swUrl)
97 | .then(response => {
98 | // Ensure service worker exists, and that we really are getting a JS file.
99 | if (
100 | response.status === 404 ||
101 | response.headers.get('content-type').indexOf('javascript') === -1
102 | ) {
103 | // No service worker found. Probably a different app. Reload the page.
104 | navigator.serviceWorker.ready.then(registration => {
105 | registration.unregister().then(() => {
106 | window.location.reload();
107 | });
108 | });
109 | } else {
110 | // Service worker found. Proceed as normal.
111 | registerValidSW(swUrl, config);
112 | }
113 | })
114 | .catch(() => {
115 | console.log(
116 | 'No internet connection found. App is running in offline mode.'
117 | );
118 | });
119 | }
120 |
121 | export function unregister() {
122 | if ('serviceWorker' in navigator) {
123 | navigator.serviceWorker.ready.then(registration => {
124 | registration.unregister();
125 | });
126 | }
127 | }
128 |
--------------------------------------------------------------------------------