Bg Sync Demo

detail.js

function offerBgSync(err) {
  if (!window.navigator.onLine) {
    showBgSyncOffer();

    listen.approveBgSync((event) => {
      askNotificationPermission()
        .then(queueRecipeLoad)
        .then(getServiceWorkerRegistration)
        .then(registerBgSync)
        .then(showBgSyncApproval);
    });
  }

  throw err;
}