text: 
  self.addEventListener('install' , event =>{
      console.log("[sw] Service worker is installing... v2")
  
      event.waitUntil(
          caches.open(' chatapp-v2').then( cache => {
              return cache.addAll([
                  '/',
                  '/index.html',
                  '/logo192.png'
              ]);
          })
      );
  });
  self.addEventListener('fetch', event =>{
      // check file
      caches.match(event.request.url).then(res => {
          if(res){
              console.log("Intercept with cache", res);
              // has file => push it
              return res;
          }
          // no file => push internet
          return fetch(event.request);
      })
  });