sw.js

importScripts('https://storage.googleapis.com/workbox-cdn/releases/3.4.1/workbox-sw.js');

if (workbox) {
  console.log(`Yay! Workbox is loaded 🎉`);
} else {
  console.log(`Boo! Workbox didn't load 😬`);
}

//workbox.googleAnalytics.initialize();

workbox.routing.registerRoute(
  //cache manifest file
  /\.(?:json)$/,
  workbox.strategies.staleWhileRevalidate({
    cacheName: 'manifest-cache',
  }),
);

workbox.routing.registerRoute(
  //cache index file
  /\.(?:html|md)$/,
  workbox.strategies.staleWhileRevalidate({
    cacheName: 'index-cache',
  }),
);

workbox.routing.registerRoute(
  /\.(?:js|css)$/,
  workbox.strategies.staleWhileRevalidate({
    cacheName: 'static-resources',
  }),
);

workbox.routing.registerRoute(
  // Cache image files
  /.*\.(?:png|jpg|jpeg|svg|gif)/,
  // Use the cache if it's available
  workbox.strategies.cacheFirst({
    // Use a custom cache name
    cacheName: 'image-cache',
    plugins: [
      new workbox.expiration.Plugin({
        // Cache only 10 images
        maxEntries: 10,
        // Cache for a maximum of three days
        maxAgeSeconds: 3 * 24 * 60 * 60,
      })
    ],
  })
);

workbox.routing.registerRoute(
  new RegExp('https://fonts.(?:googleapis|gstatic).com/(.*)'),
  workbox.strategies.cacheFirst({
    cacheName: 'google-fonts',
    plugins: [
      new workbox.expiration.Plugin({
        maxEntries: 4,
      }),
      new workbox.cacheableResponse.Plugin({
        statuses: [0, 200]
      }),
    ],
  }),
);

workbox.routing.setCatchHandler(({url, event, params}) => {
  console.log("Unknown error, due to dev being lazy")
});

self.addEventListener('fetch', function(event) {
  console.log('Fetch event for ', event.request.url);
  event.respondWith(
    caches.match(event.request).then(function(response) {
      if (response) {
        console.log('Found ', event.request.url, ' in cache');
        return response;
      }
      console.log('Network request for ', event.request.url);
      return fetch(event.request)

    }).catch(function(error) {

      return caches.match('index.html');

    })
  );
});