function Square(props) { return ( ); } class Board extends React.Component { renderSquare(i) { return ( this.props.onClick(i)} /> ); } render() { return (
{this.renderSquare(0)} {this.renderSquare(1)} {this.renderSquare(2)}
{this.renderSquare(3)} {this.renderSquare(4)} {this.renderSquare(5)}
{this.renderSquare(6)} {this.renderSquare(7)} {this.renderSquare(8)}
); } } class Game extends React.Component { constructor(props) { super(props); this.state = { history: [ { squares: Array(9).fill(null) } ], stepNumber: 0, xIsNext: true }; } handleClick(i) { const history = this.state.history.slice(0, this.state.stepNumber + 1); const current = history[history.length - 1]; const squares = current.squares.slice(); if (calculateWinner(squares) || squares[i]) { return; } squares[i] = this.state.xIsNext ? "X" : "O"; this.setState({ history: history.concat([ { squares: squares } ]), stepNumber: history.length, xIsNext: !this.state.xIsNext }); } jumpTo(step) { this.setState({ stepNumber: step, xIsNext: (step % 2) === 0 }); } render() { const history = this.state.history; const current = history[this.state.stepNumber]; const winner = calculateWinner(current.squares); const moves = history.map((step, move) => { const desc = move ? 'Go to move #' + move : 'Go to game start'; return (
  • ); }); let status; if (winner) { status = "Winner: " + winner; } else { status = "Next player: " + (this.state.xIsNext ? "X" : "O"); } return (
    this.handleClick(i)} />
    {status}
      {moves}
    ); } } // ======================================== ReactDOM.render(, document.getElementById("tictactoe")); function calculateWinner(squares) { const lines = [ [0, 1, 2], [3, 4, 5], [6, 7, 8], [0, 3, 6], [1, 4, 7], [2, 5, 8], [0, 4, 8], [2, 4, 6] ]; for (let i = 0; i < lines.length; i++) { const [a, b, c] = lines[i]; if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) { return squares[a]; } } return null; }