sw.js

let cacheName = "v1";

// Assets to cache
var assetsToCache = [
  "./index.html",
  "./dist/output.css",
  "./src/js/main.js",
  "./src/js/toggle.js",
  "./src/js/sweetalert.min.js",
  "./src/images/icons8-calculator-64.png",
];

self.addEventListener("install", function (event) {
  // waitUntil() ensures that the Service Worker will not
  // install until the code inside has successfully occurred
  event.waitUntil(
    // Create cache with the name supplied above and
    // return a promise for it
    caches
      .open(cacheName)
      .then(function (cache) {
        // Important to `return` the promise here to have `skipWaiting()`
        // fire after the cache has been updated.
        return cache.addAll(assetsToCache);
      })
      .then(function () {
        // `skipWaiting()` forces the waiting ServiceWorker to become the
        // active ServiceWorker, triggering the `onactivate` event.
        // Together with `Clients.claim()` this allows a worker to take effect
        // immediately in the client(s).
        return self.skipWaiting();
      })
  );
});

// Activate event
// Be sure to call self.clients.claim()
self.addEventListener("activate", function (event) {
  // `claim()` sets this worker as the active worker for all clients that
  // match the workers scope and triggers an `oncontrollerchange` event for
  // the clients.
  return self.clients.claim();
});

self.addEventListener("fetch", function (event) {
  // Ignore non-get request like when accessing the admin panel
  if (event.request.method !== "GET") {
    return;
  }
  // Don't try to handle non-secure assets because fetch will fail
  if (/http:/.test(event.request.url)) {
    return;
  }

  // Here's where we cache all the things!
  event.respondWith(
    // Open the cache created when install
    caches.open(cacheName).then(function (cache) {
      // Go to the network to ask for that resource
      return fetch(event.request)
        .then(function (networkResponse) {
          // Add a copy of the response to the cache (updating the old version)
          cache.put(event.request, networkResponse.clone());
          // Respond with it
          return networkResponse;
        })
        .catch(function () {
          // If there is no internet connection, try to match the request
          // to some of our cached resources
          return cache.match(event.request);
        });
    })
  );
});