service-worker.js

/* istanbul ignore file */
/* eslint-disable no-restricted-globals */

/*
 * This service worker can be customized!
 * See https://developers.google.com/web/tools/workbox/modules
 * for the list of available Workbox modules, or add any other
 * code you'd like.
 * You can also remove this file if you'd prefer not to use a
 * service worker, and the Workbox build step will be skipped.
 */

import { clientsClaim } from 'workbox-core';
import { ExpirationPlugin } from 'workbox-expiration';
import {
  createHandlerBoundToURL,
  precacheAndRoute,
} from 'workbox-precaching';
import { registerRoute } from 'workbox-routing';
import { StaleWhileRevalidate } from 'workbox-strategies';

clientsClaim();

/*
 * Precache all of the assets generated by your build process.
 * Their URLs are injected into the manifest variable below.
 * This variable must be present somewhere in your service worker file,
 * even if you decide not to use precaching. See https://cra.link/PWA
 */
precacheAndRoute(self.__WB_MANIFEST);

/*
 * Set up App Shell-style routing, so that all navigation requests
 * are fulfilled with your index.html shell. Learn more at
 * https://developers.google.com/web/fundamentals/architecture/app-shell
 */
const fileExtensionRegexp = new RegExp('/[^/?]+\\.[^/]+$');
registerRoute(
  // Return false to exempt requests from being fulfilled by index.html.
  ({
    request, url,
  }) => {
    // If this isn't a navigation, skip.
    if (request.mode !== 'navigate') {
      return false;
    } // If this is a URL that starts with /_, skip.

    if (url.pathname.startsWith('/_')) {
      return false;
    } // If this looks like a URL for a resource, because it contains // a file extension, skip.

    if (url.pathname.match(fileExtensionRegexp)) {
      return false;
    } // Return true to signal that we want to use the handler.

    return true;
  },
  createHandlerBoundToURL(`${process.env.PUBLIC_URL}/index.html`)
);

/*
 * An example runtime caching route for requests that aren't handled by the
 * precache, in this case same-origin .png requests like those from in public/
 */
registerRoute(
  // Add in any other file extensions or routing criteria as needed.
  ({ url }) => url.origin === self.location.origin && (url.pathname.endsWith('.png') || url.pathname === '/favicon.ico'),
  // Customize this strategy as needed, e.g., by changing to CacheFirst.
  new StaleWhileRevalidate({
    cacheName: 'images',
    plugins: [

      /*
       * Ensure that once this runtime cache reaches a maximum size the
       * least-recently used images are removed.
       */
      new ExpirationPlugin({ maxEntries: 50 }),
    ],
  })
);

registerRoute(
  ({ url }) => url.origin === self.location.origin && url.pathname.endsWith('.json'),
  new StaleWhileRevalidate({
    cacheName: 'json',
    plugins: [

      /*
       * Ensure that once this runtime cache reaches a maximum size the
       * least-recently used images are removed.
       */
      new ExpirationPlugin({ maxEntries: 50 }),
    ],
  })
);

/*
 * This allows the web app to trigger skipWaiting via
 * registration.waiting.postMessage({type: 'SKIP_WAITING'})
 */
self.addEventListener(
  'message',
  (event) => {
    if (event.data && event.data.type === 'SKIP_WAITING') {
      self.skipWaiting();
    }
  }
);

// Any other custom service worker logic can go here.