strategies.js

const strategies = {
  cacheFirst(request) {
    return caches.open(APPLICATION_CACHE).then((cache) => {
      return cache.match(request).then((matching) => {
        return matching || Promise.reject('no-match');
      });
    });
  },
  networkFirst(request, delay) {
    return new Promise((resolve, reject) => {
      let timeout = setTimeout(reject, delay);

      fetch(request).then((response) => {
        clearTimeout(timeout);
        resolve(response);
      }, reject);
    });
  },
  cacheFirstThenNetwork() {}
};

export default strategies;