118 lines
4.3 KiB
JavaScript
118 lines
4.3 KiB
JavaScript
// In production, we register a service worker to serve assets from local cache.
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// This lets the app load faster on subsequent visits in production, and gives
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// it offline capabilities. However, it also means that developers (and users)
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// will only see deployed updates on the "N+1" visit to a page, since previously
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// cached resources are updated in the background.
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// To learn more about the benefits of this model, read https://goo.gl/KwvDNy.
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// This link also includes instructions on opting out of this behavior.
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const isLocalhost = Boolean(
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window.location.hostname === 'localhost' ||
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// [::1] is the IPv6 localhost address.
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window.location.hostname === '[::1]' ||
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// 127.0.0.1/8 is considered localhost for IPv4.
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window.location.hostname.match(
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/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
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)
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);
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export default function register() {
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if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
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// The URL constructor is available in all browsers that support SW.
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const publicUrl = new URL(process.env.PUBLIC_URL, window.location);
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if (publicUrl.origin !== window.location.origin) {
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// Our service worker won't work if PUBLIC_URL is on a different origin
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// from what our page is served on. This might happen if a CDN is used to
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// serve assets; see https://github.com/facebookincubator/create-react-app/issues/2374
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return;
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}
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window.addEventListener('load', () => {
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const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
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if (isLocalhost) {
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// This is running on localhost. Lets check if a service worker still exists or not.
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checkValidServiceWorker(swUrl);
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// Add some additional logging to localhost, pointing developers to the
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// service worker/PWA documentation.
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navigator.serviceWorker.ready.then(() => {
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console.log(
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'This web app is being served cache-first by a service ' +
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'worker. To learn more, visit https://goo.gl/SC7cgQ'
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);
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});
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} else {
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// Is not local host. Just register service worker
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registerValidSW(swUrl);
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}
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});
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}
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}
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function registerValidSW(swUrl) {
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navigator.serviceWorker
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.register(swUrl)
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.then(registration => {
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registration.onupdatefound = () => {
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const installingWorker = registration.installing;
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installingWorker.onstatechange = () => {
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if (installingWorker.state === 'installed') {
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if (navigator.serviceWorker.controller) {
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// At this point, the old content will have been purged and
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// the fresh content will have been added to the cache.
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// It's the perfect time to display a "New content is
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// available; please refresh." message in your web app.
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console.log('New content is available; please refresh.');
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} else {
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// At this point, everything has been precached.
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// It's the perfect time to display a
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// "Content is cached for offline use." message.
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console.log('Content is cached for offline use.');
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}
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}
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};
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};
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})
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.catch(error => {
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console.error('Error during service worker registration:', error);
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});
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}
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function checkValidServiceWorker(swUrl) {
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// Check if the service worker can be found. If it can't reload the page.
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fetch(swUrl)
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.then(response => {
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// Ensure service worker exists, and that we really are getting a JS file.
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if (
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response.status === 404 ||
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response.headers.get('content-type').indexOf('javascript') === -1
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) {
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// No service worker found. Probably a different app. Reload the page.
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navigator.serviceWorker.ready.then(registration => {
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registration.unregister().then(() => {
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window.location.reload();
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});
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});
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} else {
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// Service worker found. Proceed as normal.
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registerValidSW(swUrl);
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}
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})
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.catch(() => {
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console.log(
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'No internet connection found. App is running in offline mode.'
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);
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});
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}
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export function unregister() {
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if ('serviceWorker' in navigator) {
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navigator.serviceWorker.ready.then(registration => {
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registration.unregister();
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});
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}
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}
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