cache_fetch.js

const cacheName ='cache_v1';
self.addEventListener('fetch', e=> {
    if (e.request.cache === 'only-if-cached' && e.request.mode !== 'same-origin'){
        console.log("not same origin");
        return;
    }
    console.log('[ServiceWorker] Fetched resources');
    e.respondWith(
        caches.open(cacheName)
        .then(cache => cache.match(e.request, {ignoreSearch: true}))
        .then(response => {
        return response || fetch(e.request);
    }));
});