index.js

function register() {
  navigator.serviceWorker && navigator.serviceWorker
    .register('./service-worker.js')
    .then(registration => {
      registration.onupdatefound = () => {
        const installingWorker = registration.installing;
        installingWorker.onstatechange = () => {
          if (installingWorker.state === "installed") {
            if (navigator.serviceWorker.controller) {
              // At this point, the old content will have been purged and
              // the fresh content will have been added to the cache.
              // It's the perfect time to display a "New content is
              // available; please refresh." message in your web app.
              console.log("New content is available; please refresh.");
            } else {
              // At this point, everything has been precached.
              // It's the perfect time to display a
              // "Content is cached for offline use." message.
              console.log("Content is cached for offline use.");
            }
          }
        };
      };
    })
    .catch(error => {
      console.error("Error during service worker registration:", error);
    });
}

function unregister() {
  if ("serviceWorker" in navigator) {
    navigator.serviceWorker.ready.then(registration => {
      registration.unregister();
    });
  }
}
register();