Ошибка при запуске Service Worker PWA

self.addEventListener('install', function(event) { 
  event.waitUntil(preLoad()); 
}); 
 
const preLoad = function(){ 
  console.log('[PWA Builder] Install Event processing'); 
  return caches.open('pwabuilder-offline').then(function(cache) { 
    console.log('[PWA Builder] Cached index and offline page during install'); 
    return cache.addAll(['/offline.html', '/index.html']); 
  }); 
}; 
 
self.addEventListener('fetch', function(event) { 
  console.log('[PWA Builder] The service worker is serving the asset.'); 
  event.respondWith(checkResponse(event.request).catch(function() { 
    return returnFromCache(event.request);} 
  )); 
  event.waitUntil(addToCache(event.request)); 
}); 
 
const checkResponse = function(request){ 
  return new Promise(function(fulfill, reject) { 
    fetch(request).then(function(response){ 
      if(response.status !== 404) { 
        fulfill(response); 
      } else { 
        reject(); 
      } 
    }, reject); 
  }); 
}; 
 
const addToCache = function(request){ 
  return caches.open('pwabuilder-offline').then(function (cache) { 
    return fetch(request).then(function (response) { 
      console.log('[PWA Builder] add page to offline cache: ' + response.url); 
      return cache.put(request, response); 
    }); 
  }); 
}; 
 
const returnFromCache = function(request){ 
  return caches.open('pwabuilder-offline').then(function (cache) { 
    return cache.match(request).then(function (matching) { 
     if(!matching || matching.status == 404) { 
       return cache.match('offline.html') 
     } else { 
       return matching 
     } 
    }); 
  }); 
};