servicer_worker.js

let staticCacheName = 'restaurant-cache';
let urlsToCache = [
  './',
  './index.html',
  './restaurant.html',
  './css/styles.css',
  './js/main.js',
  './js/restaurant_info.js',
  './js/dbhelper.js',
  './js/sw_registration.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',
];

/**
*Installation
*/

self.addEventListener('install', function(event) {
	event.waitUntil(
		caches.open(staticCacheName).then(function(cache) {
			return cache.addAll(urlsToCache);
        })
    );
});


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


/**
 * Fetching content
 */
self.addEventListener('fetch', function(event) {
    event.respondWith(
        caches.match(event.request).then(function(response) {
            return response || fetch(event.request);
        })
    );
});