import {precacheAndRoute} from 'workbox-precaching'; precacheAndRoute(self.__WB_MANIFEST); // Additional code goes here. self.addEventListener('fetch', function(event) { event.respondWith( // Try the cache caches.match(event.request).then(function(response) { // Fall back to network return response || fetch(event.request); }).catch(function() { // If both fail, show a generic fallback: return caches.match('/offline.html'); // However, in reality you'd have many different // fallbacks, depending on URL & headers. // Eg, a fallback silhouette image for avatars. }) ); });