content: import React from 'react';
  import ReactDom from 'react-dom';
  
  import App from './component/app';
  
  ReactDom.render(
    <App/>,
    document.getElementById('app')
  )
  
  if (module.hot) {
      module.hot.accept('./component/app', function(){
          let newApp = require('./component/app').default;
          render(newApp);
      });
  }
  