text: let cacheName = 'tte';
  let cacheURLs = [
    './',
    'index.html',
    'src/index.css',
    'src/bundle.js',
    'manifest.json',
    'favicon.ico',
    'https://fonts.googleapis.com/css?family=Roboto|Ubuntu'
  ];
  
  self.addEventListener('install', function(e){
    e.waitUntil(
      caches.open(cacheName).then(function(ch){
        return ch.addAll(cacheURLs);
      })
    );
    // console.log('Caching complete');
  });
  
  self.addEventListener('fetch', function(e){
    e.respondWith(
      fetch(e.request).catch(function(){
        return caches.match(e.request).then(function(response){
          if(response){
            return response;
          }
          else{
            console.log('Not Available');
          }
        })
      })
    );
  });