text: import React from 'react';
  import ReactDOM from 'react-dom';
  import './index.css';
  
  class Square extends React.Component {
      render() {
        return (
          <button className="square" onClick={function() { console.log('click'); }}>
            {this.props.value}
          </button>
        );
      }
    }
    
    class Board extends React.Component {
      renderSquare(i) {
        return <Square value={i}/>;
      }
    
      render() {
        const status = 'Next player: X';
    
        return (
          <div>
            <div className="status">{status}</div>
            <div className="board-row">
              {this.renderSquare(0)}
              {this.renderSquare(1)}
              {this.renderSquare(2)}
            </div>
            <div className="board-row">
              {this.renderSquare(3)}
              {this.renderSquare(4)}
              {this.renderSquare(5)}
            </div>
            <div className="board-row">
              {this.renderSquare(6)}
              {this.renderSquare(7)}
              {this.renderSquare(8)}
            </div>
          </div>
        );
      }
    }
    
    class Game extends React.Component {
      render() {
        return (
          <div className="game">
            <div className="game-board">
              <Board />
            </div>
            <div className="game-info">
              <div>{/* status */}</div>
              <ol>{/* TODO */}</ol>
            </div>
          </div>
        );
      }
    }
    
    // ========================================
    
    ReactDOM.render(
      <Game />,
      document.getElementById('root')
    );
    