title: REACT Check the render method of `Route`. helpme T.T
body: <p><a href="https://i.stack.imgur.com/ZGJ3k.png" rel="nofollow noreferrer">error image</a></p>
  
  <p>This Image is Error Image</p>
  
  <p>I am making react spa but i cannot figure this error! T.T</p>
  
  <p>help me!</p>
  
  <p>I think this error is begun in App.js
  But I don't know what should I do...</p>
  
  <p>This is index.js</p>
  
  <pre><code>import React from 'react';
  import ReactDOM from 'react-dom';
  import './index.scss';
  import App from './containers/App';
  import * as serviceWorker from './serviceWorker';
  import { BrowserRouter } from 'react-router-dom';
  
  ReactDOM.render(
      &lt;BrowserRouter&gt;
          &lt;App /&gt;
      &lt;/BrowserRouter&gt;,
      document.getElementById('root')
  );
  
  serviceWorker.unregister();
  </code></pre>
  
  <p>This is App.js</p>
  
  <pre><code>import React, { Component } from 'react';
  import { Switch, Link, Route } from 'react-router-dom';
  import * as classNames from 'classnames/bind';
  import styles from './App.scss';
  
  import Main from './Main/Main'
  
  const cx = classNames.bind(styles);
  
  class App extends Component {
    render() {
      return (
        &lt;div className={cx("App")}&gt;
          &lt;nav&gt;
              &lt;div&gt;&lt;Link to="/"&gt;JUMP&lt;/Link&gt;&lt;/div&gt;
          &lt;/nav&gt;
         &lt;main&gt;
             &lt;div className={cx("main")}&gt;
                 &lt;Switch&gt;
                     &lt;Route path="/" exact component={Main}/&gt;
                 &lt;/Switch&gt;
             &lt;/div&gt;
         &lt;/main&gt;
        &lt;/div&gt;
      );
    }
  }
  
  export default App;
  </code></pre>
  
  <p>This is folder structure</p>
  
  <pre><code>├── src
  │   ├── components
  │   │   └── Headers
  │   ├── containers
  │   │   ├── 0.Login
  │   │   │   ├──Login.js
  │   │   │   └──Login.sass
  │   │   ├── App.scss
  │   │   ├── App.js
  │   ├── index.scss
  │   ├── index.js
  │   ├── logo.scv
  └── └── serviceWorker.js
  </code></pre>