sw.js

var staticCacheName = 'restaurant-review-app-v4';

self.addEventListener('install', function(event) {
  event.waitUntil(
    caches.open(staticCacheName).then(function(cache) {
      return cache.addAll([
        '/',
        'index.html',
        '/restaurant.html',
        '/css/styles.css',
        '/css/responsive.css',
        '/js/dbhelper.js',
        '/js/main.js',
        '/js/restaurant_info.js',
        'data/restaurants.json',
        '/img/1.jpg',
        '/img/2.jpg',
        '/img/3.jpg',
        '/img/4.jpg',
        '/img/5.jpg',
        '/img/6.jpg',
        '/img/7.jpg',
        '/img/8.jpg',
        '/img/9.jpg',
        '/img/10.jpg'
      ]);
    })
  );
});


self.addEventListener('activate', event => {
  event.waitUntil(
    caches.keys().then(function(cacheNames) {
      return Promise.all(
        cacheNames.filter(function(cacheName) {
          return cacheName.startsWith('restaurant-review-app-') &&
            cacheName != staticCacheName;
        }).map(function(cacheName) {
          return caches.delete(cacheName);
        })
      );
    })
  );
});


self.addEventListener('fetch', event => {
  console.log(event.request.url);
  event.respondWith(
    caches.match(event.request).then(function(response) {
      // return response || fetch(event.request);
      if (response) {
        return response;
      } else {
        return fetch(event.request).then(function(response) {
          let responseClone = response.clone();
          caches.open(staticCacheName).then(function(cache) {
            cache.put(event.request, responseClone);
          });
          return response;
        });
      }

    })
  );
});