nexus-timers/build/service-worker-dev.js

// This service worker file is effectively a 'no-op' that will reset any
// previous service worker registered for the same host:port combination.
// In the production build, this file is replaced with an actual service worker
// file that will precache your site's local assets.
// See https://github.com/facebookincubator/create-react-app/issues/2272#issuecomment-302832432

self.addEventListener('install', () => self.skipWaiting());

self.addEventListener('activate', () => {
  self.clients.matchAll({ type: 'window' }).then(windowClients => {
    for (let windowClient of windowClients) {
      // Force open pages to refresh, so that they have a chance to load the
      // fresh navigation response from the local dev server.
      windowClient.navigate(windowClient.url);
    }
  });
});