server-worker.js

const CACHE_NAME = 'tic-tac-toe-cache-v1';
const ASSETS = [
  '/',
  '/index.html',
  '/css/tic-tac-toe.css',
  '/js/tic-tac-toe.js',
  '/icons/icon-192x192.png',
  '/icons/icon-512x512.png'
];

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

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

// Fetch assets from cache first, then from network
self.addEventListener('fetch', (event) => {
  event.respondWith(
    caches.match(event.request).then((cachedResponse) => {
      return cachedResponse || fetch(event.request);
    })
  );
});