index.js

self.addEventListener('message', async (e) => {
  const cache = await caches.open(CACHE_NAME)
  switch (e.data.action) {
  case 'cache':
    const res = new Response(e.data.response);
    cache.put(e.data.url, res);
    break;
  case 'delete':
    cache.delete(e.data.url);
    break;
  }
});