function checkValidServiceWorker()

in frontend/src/serviceWorker.ts [104:127]

• 20 lines of code
• 4 McCabe index (conditional complexity)

function checkValidServiceWorker(swUrl: string, config?: IConfig) {
  // Check if the service worker can be found. If it can't reload the page.
  fetch(swUrl, {
    headers: { 'Service-Worker': 'script' }
  })
    .then((response) => {
      // Ensure service worker exists, and that we really are getting a JS file.
      const contentType = response.headers.get('content-type');
      if (response.status === 404 || (contentType != null && contentType.indexOf('javascript') === -1)) {
        // No service worker found. Probably a different app. Reload the page.
        navigator.serviceWorker.ready.then((registration) => {
          registration.unregister().then(() => {
            window.location.reload();
          });
        });
      } else {
        // Service worker found. Proceed as normal.
        registerValidSW(swUrl, config);
      }
    })
    .catch(() => {
      console.log('No internet connection found. App is running in offline mode.');
    });
}