Data cache with service worker

app.js

(function () {
  'use strict';
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker
    .register('/assets/javascripts/service-worker.js')
    .then(function (registration) {
      console.info('Service Worker Registered');
    }).catch(function (e) {
      console.error('Error during service worker registration:', e);
    });
  }
})();

service-worker.js

/* eslint no-unused-vars: 0 */
var dataCacheName = 'serviceWorker-v1';
var cacheName = 'serviceWorker-cacheName-1';
var filesToCache = [
  '/assets/javascripts/jquery.js',
  '/assets/javascripts/main.js',
  '/assets/stylesheets/main.css',
  '/assets/images/logo.png',
  '/assets/images/loader.gif',
  '/assets/images/sprite.png'
];

self.addEventListener('install', function (event) {
  console.info('[ServiceWorker] Install');
  event.waitUntil(
    caches.open(cacheName).then(function (cache) {
      console.info('[ServiceWorker] Caching app shell');
      return cache.addAll(filesToCache);
    })
  );
});

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

  return self.clients.claim();
});