service-worker.js

'use strict';

const CACHE_NAME = 'static-cache-v6';

const FILES_TO_CACHE = [
  './',
  './index.html',
  './install.js',
  './normalize.css',
  './global.css',
  './build/bundle.css',
  './build/bundle.js',
  './fonts/Exo2-Italic-VariableFont_wght.ttf',
  './fonts/Exo2-VariableFont_wght.ttf'
];

self.addEventListener('install', (event) => {
  console.log('[ServiceWorker] Install');
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      console.log('[ServiceWorker] Pre-caching offline page');
      return cache.addAll(FILES_TO_CACHE);
    })
  );

  self.skipWaiting();
});

self.addEventListener('activate', (event) => {
  console.log('[ServiceWorker] Activate');
  event.waitUntil(
      caches.keys().then((keyList) => {
        return Promise.all(keyList.map((key) => {
          if (key !== CACHE_NAME) {
            console.log('[ServiceWorker] Removing old cache', key);
            return caches.delete(key);
          }
        }));
      })
  );

  self.clients.claim();
});

self.addEventListener('fetch', (event) => {
  console.log('[ServiceWorker] Fetch', event.request.url);
  if (event.request.mode !== 'navigate') {
    // Not a page navigation, bail.
    return;
  }

  event.respondWith(
    fetch(event.request)
      .catch(() => {
        return caches.open(CACHE_NAME)
          .then((cache) => {
            return cache.match('index.html');
          });
      })
  );
});