Tic-Tac-Toe-1b.jsx

// Inside Game's render method

const moves = history.map((step, move) => {
  const desc = move 
    ? "Go to move #" + move + " @ " + history[move].location
    : 'Go to game start';
  return (
    <li key={move}>
      <button onClick={() => this.jumpTo(move)}>{desc}</button>
    </li>
  );
});