sw.js

const CACHE_NAME = 'portfolio-v1';
const ASSETS_TO_CACHE = [
  'offline.html',
  'style.css'
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(ASSETS_TO_CACHE);
    })
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames.map((cache) => {
          if (cache !== CACHE_NAME) {
            return caches.delete(cache);
          }
        })
      );
    })
  );
});

self.addEventListener('fetch', (event) => {
  if (!event.request.url.startsWith('http')) return;

  if (event.request.mode === 'navigate') {
    event.respondWith(
      fetch(event.request).catch(() => {
        return caches.match('offline.html');
      })
    );
  } else {
    event.respondWith(
      caches.match(event.request).then((response) => {
        return response || fetch(event.request);
      })
    );
  }
});