text: import React from "react";
  import { render } from "react-dom";
  import {Router, Route} from "react-router"
  import createBrowserHistory from 'history/createBrowserHistory'
  
  import { Root } from "./components/Root";
  import { Home } from "./components/Home";
  import { User } from "./components/User";
  
  const customHistory = createBrowserHistory();
  class App extends React.Component {
      render() {
          return (
              <Router history={customHistory}>
                  <div>
                      <Route exact path="/" component={Root}/>
                      <Route path="/user" component={User} />
                      <Route path="/home" component={Home} />
                  </div>
              </Router>
          )
      }
  }
  // className instead of class
  // no comments within JSX!
  
  render(<App/>, window.document.getElementById("app"));