Larbi Gharib | e9af973 | 2021-03-31 15:08:01 +0100 | [diff] [blame] | 1 | // This optional code is used to register a service worker. |
| 2 | // register() is not called by default. |
| 3 | |
| 4 | // This lets the app load faster on subsequent visits in production, and gives |
| 5 | // it offline capabilities. However, it also means that developers (and users) |
| 6 | // will only see deployed updates on subsequent visits to a page, after all the |
| 7 | // existing tabs open on the page have been closed, since previously cached |
| 8 | // resources are updated in the background. |
| 9 | |
| 10 | // To learn more about the benefits of this model and instructions on how to |
| 11 | // opt-in, read https://bit.ly/CRA-PWA |
| 12 | |
| 13 | const isLocalhost = Boolean( |
| 14 | window.location.hostname === 'localhost' || |
| 15 | // [::1] is the IPv6 localhost address. |
| 16 | window.location.hostname === '[::1]' || |
| 17 | // 127.0.0.0/8 are considered localhost for IPv4. |
| 18 | window.location.hostname.match( |
| 19 | /^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/ |
| 20 | ) |
| 21 | ); |
| 22 | |
| 23 | export function register(config) { |
| 24 | if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) { |
| 25 | // The URL constructor is available in all browsers that support SW. |
| 26 | const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href); |
| 27 | if (publicUrl.origin !== window.location.origin) { |
| 28 | // Our service worker won't work if PUBLIC_URL is on a different origin |
| 29 | // from what our page is served on. This might happen if a CDN is used to |
| 30 | // serve assets; see https://github.com/facebook/create-react-app/issues/2374 |
| 31 | return; |
| 32 | } |
| 33 | |
| 34 | window.addEventListener('load', () => { |
| 35 | const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`; |
| 36 | |
| 37 | if (isLocalhost) { |
| 38 | // This is running on localhost. Let's check if a service worker still exists or not. |
| 39 | checkValidServiceWorker(swUrl, config); |
| 40 | |
| 41 | // Add some additional logging to localhost, pointing developers to the |
| 42 | // service worker/PWA documentation. |
| 43 | navigator.serviceWorker.ready.then(() => { |
| 44 | console.log( |
| 45 | 'This web app is being served cache-first by a service ' + |
| 46 | 'worker. To learn more, visit https://bit.ly/CRA-PWA' |
| 47 | ); |
| 48 | }); |
| 49 | } else { |
| 50 | // Is not localhost. Just register service worker |
| 51 | registerValidSW(swUrl, config); |
| 52 | } |
| 53 | }); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | function registerValidSW(swUrl, config) { |
| 58 | navigator.serviceWorker |
| 59 | .register(swUrl) |
| 60 | .then(registration => { |
| 61 | registration.onupdatefound = () => { |
| 62 | const installingWorker = registration.installing; |
| 63 | if (installingWorker == null) { |
| 64 | return; |
| 65 | } |
| 66 | installingWorker.onstatechange = () => { |
| 67 | if (installingWorker.state === 'installed') { |
| 68 | if (navigator.serviceWorker.controller) { |
| 69 | // At this point, the updated precached content has been fetched, |
| 70 | // but the previous service worker will still serve the older |
| 71 | // content until all client tabs are closed. |
| 72 | console.log( |
| 73 | 'New content is available and will be used when all ' + |
| 74 | 'tabs for this page are closed. See https://bit.ly/CRA-PWA.' |
| 75 | ); |
| 76 | |
| 77 | // Execute callback |
| 78 | if (config && config.onUpdate) { |
| 79 | config.onUpdate(registration); |
| 80 | } |
| 81 | } else { |
| 82 | // At this point, everything has been precached. |
| 83 | // It's the perfect time to display a |
| 84 | // "Content is cached for offline use." message. |
| 85 | console.log('Content is cached for offline use.'); |
| 86 | |
| 87 | // Execute callback |
| 88 | if (config && config.onSuccess) { |
| 89 | config.onSuccess(registration); |
| 90 | } |
| 91 | } |
| 92 | } |
| 93 | }; |
| 94 | }; |
| 95 | }) |
| 96 | .catch(error => { |
| 97 | console.error('Error during service worker registration:', error); |
| 98 | }); |
| 99 | } |
| 100 | |
| 101 | function checkValidServiceWorker(swUrl, config) { |
| 102 | // Check if the service worker can be found. If it can't reload the page. |
| 103 | fetch(swUrl, { |
| 104 | headers: { 'Service-Worker': 'script' }, |
| 105 | }) |
| 106 | .then(response => { |
| 107 | // Ensure service worker exists, and that we really are getting a JS file. |
| 108 | const contentType = response.headers.get('content-type'); |
| 109 | if ( |
| 110 | response.status === 404 || |
| 111 | (contentType != null && contentType.indexOf('javascript') === -1) |
| 112 | ) { |
| 113 | // No service worker found. Probably a different app. Reload the page. |
| 114 | navigator.serviceWorker.ready.then(registration => { |
| 115 | registration.unregister().then(() => { |
| 116 | window.location.reload(); |
| 117 | }); |
| 118 | }); |
| 119 | } else { |
| 120 | // Service worker found. Proceed as normal. |
| 121 | registerValidSW(swUrl, config); |
| 122 | } |
| 123 | }) |
| 124 | .catch(() => { |
| 125 | console.log( |
| 126 | 'No internet connection found. App is running in offline mode.' |
| 127 | ); |
| 128 | }); |
| 129 | } |
| 130 | |
| 131 | export function unregister() { |
| 132 | if ('serviceWorker' in navigator) { |
| 133 | navigator.serviceWorker.ready |
| 134 | .then(registration => { |
| 135 | registration.unregister(); |
| 136 | }) |
| 137 | .catch(error => { |
| 138 | console.error(error.message); |
| 139 | }); |
| 140 | } |
| 141 | } |