service-worker.js

// Define cache name
const cacheName = 'piccolo-v1';

// List of URLs to cache
const urlsToCache = [
  '/',
  '/index.html',
  '/style.css',
  '/script.js',
  '/images',
  '/images/piccoloAPPicon.png',
];

// Install service worker and cache assets
self.addEventListener('install', event => {
  event.waitUntil(
    caches.open(cacheName)
      .then(cache => cache.addAll(urlsToCache))
  );
});

// Fetch assets from cache or network
self.addEventListener('fetch', event => {
  event.respondWith(
    caches.match(event.request)
      .then(response => {
        // Cache hit - return response
        if (response) {
          return response;
        }
        // Clone the request
        const fetchRequest = event.request.clone();

        // Fetch from network
        return fetch(fetchRequest)
          .then(response => {
            // Check if valid response
            if (!response || response.status !== 200 || response.type !== 'basic') {
              return response;
            }

            // Clone response
            const responseToCache = response.clone();

            // Cache fetched response
            caches.open(cacheName)
              .then(cache => {
                cache.put(event.request, responseToCache);
              });

            return response;
          });
      })
  );
});

// Activate service worker and clean up old caches
self.addEventListener('activate', event => {
  event.waitUntil(
    caches.keys().then(cacheNames => {
      return Promise.all(
        cacheNames.map(cache => {
          if (cache !== cacheName) {
            return caches.delete(cache);
          }
        })
      );
    })
  );
});