service-worker-registration.js

export function register() {
  if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
    window.addEventListener('load', () => {
      const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
      navigator.serviceWorker.register(swUrl).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);
      });
    });
  }
}

export function unregister() {
  if ('serviceWorker' in navigator) {
    navigator.serviceWorker.ready.then(function(registration) {
      registration.unregister();
    });
  }
}