Service worker to cache everything

cacheWorker.js

// This code should be accessable from your root domain
// As in, don't bundle
const cacheName = 'cache-v1';

// The activate handler takes care of cleaning up old caches.
self.addEventListener('activate', event => {
  const currentCaches = [cacheName];
  event.waitUntil(
    caches.keys().then(cacheNames => {
      return cacheNames.filter(cacheName => !currentCaches.includes(cacheName));
    }).then(cachesToDelete => {
      return Promise.all(cachesToDelete.map(cacheToDelete => {
        return caches.delete(cacheToDelete);
      }));
    }).then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', function (event) {
  event.respondWith(
    caches.match(event.request).then(function (response) {
      if (response) {
        return response;
      }

      return fetch(event.request).then(async response => {
        const cache = await caches.open(cacheName);
        return cache.put(event.request, response.clone()).then(() => {
          return response;
        });
      });
    })
  );
});

index.js

// This code should be called from within your bundled app.
if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('/cacheWorker.js', {})
    .then((registration) => {
      registration.onupdatefound = () => {
        window.location.reload();
      };
      console.log('Cache Worker - Registration succeeded');
    }).catch((error) => {
      console.log('Cache Worker - Registration failed', error);
    });
}