old_contents: // -----------------------------------------------------
  // Here is starting point for your own code.
  // All stuff below is just to show you haw it works.
  // -----------------------------------------------------
  
  // Browser modules are required through new ES6 syntax.
  import { greet } from './hello_world/hello_world';
  
  // Node modules are required the same way as always.
  var os = require('os');
  
  var greetElement = document.getElementById('greet');
  greetElement.innerHTML = greet();
  
  var platform = document.getElementById('platform-info');
  platform.innerHTML = os.platform();
  
new_contents: // -----------------------------------------------------
  // Here is the starting point for your own code.
  // All stuff below is just to show you how it works.
  // -----------------------------------------------------
  
  // Browser modules are imported through new ES6 syntax.
  import { greet } from './hello_world/hello_world';
  
  // Node modules are required the same way as always.
  var os = require('os');
  
  var greetElement = document.getElementById('greet');
  greetElement.innerHTML = greet();
  
  var platform = document.getElementById('platform-info');
  platform.innerHTML = os.platform();
  
subject: Update app.js