sw-registration.js

  if ('serviceWorker' in navigator && location.hostname !== "localhost") {
    window.addEventListener('load', function() {
      navigator.serviceWorker.register(‚service-worker.js’).then(function(reg) {
        // updatefound is fired if service-worker.js changes.
        reg.onupdatefound = function() {
          var installingWorker = reg.installing;

          installingWorker.onstatechange = function() {
            switch (installingWorker.state) {
              case 'installed':
                if (navigator.serviceWorker.controller) {
                  setTimeout(function() {
                    location.reload(true);
                  }, 5000);
                } 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 now available offline!');
                }
                break;

              case 'redundant':
                console.error('The installing service worker became redundant.');
                break;
            }
          };
        };
      }).catch(function(e) {
        console.error('Error during service worker registration:', e);
      });
    });
  }