Tic-Tac-Toe-2a.jsx

// Inside Game's render method
// Note <button>'s child

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)}>
        {move == this.state.stepNumber ? <b>{desc}</b> : desc}
      </button>
    </li>
  );
});