text: const CACHE_NAME = 'em-ANK-HAR-Cache-v1';
  const URLS_TO_CACHE = [
      "/public/offline",
  ];
  self.addEventListener("install", function(event) {
      event.waitUntil(
          caches.open(CACHE_NAME).then(function(cache) {
              return cache.addAll(URLS_TO_CACHE);
          })
      );
  });
  
  self.addEventListener("fetch", function(event) {
      event.respondWith(
          fetch(event.request).catch(function() {
              return caches.match(event.request).then(function(response) {
                  if (response) {
                      return response;
                  } else if (event.request.headers.get("accept").includes("text/html")) {
                      return caches.match("/offline");
                  }
              });
          })
      );
  });