block4.js

// Main.js
import React from 'react';

import logo from './logo.svg';
import './App.css';

const Main = () => (
  <header className="App-header">
    <img src={logo} className="App-logo" alt="logo" />
    <p>
      Edit <code>src/App.js</code> and save to reload.
    </p>
    <a
      className="App-link"
      href="https://reactjs.org"
      target="_blank"
      rel="noopener noreferrer"
    >
      Learn React
    </a>
  </header>
);

export default Main;