service worker to cache fonts

sw.js

importScripts(
  'https://storage.googleapis.com/workbox-cdn/releases/3.0.0-beta.0/workbox-sw.js '
);

if (workbox) {
  workbox.routing.registerRoute(
    /.*\.(?:woff2,woff,ttf,otf)/,
    workbox.strategies.cacheFirst({
      cacheName: 'font-cache',
      plugins: [
        new workbox.expiration.Plugin({
          maxEntries: 10,
          maxAgeSeconds: 30 * 24 * 60 * 60
        })
      ]
    })
  );

  else {
    console.log(`Boo! Workbox didn't load`);
  }
}