井字棋源码

import React from 'react';
import ReactDOM from 'react-dom';
import './App.css';


class Square extends React.Component {
    render(props) {
        return (
            <button className="square"
                onClick={this.props.onClick}>
                {this.props.value}
            </button>
        );
    }
}

class Board extends React.Component {

    renderSquare(i) {
        return <Square value={this.props.squares[i]}
            onClick={() => this.props.onClick(i)} />;
    }
    render() {
        return (
            <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 {
    constructor(props) {
        super(props)
        this.state = {
            history: [
                {
                    squares: Array(9).fill(null)
                }
            ],
            xNext: true,
            stepNumber: 0
        }
    }
    handleClick(i) {
        const history = this.state.history.slice(0, this.state.stepNumber + 1)
        const current = history[history.length - 1]
        const newSquares = current.squares.slice()
        if (calculateWinner(newSquares) || newSquares[i]) {
            return
        }
        newSquares[i] = this.state.xNext ? 'X' : 'O'
        this.setState({
            history: history.concat([{
                squares: newSquares
            }]),
            xNext: !this.state.xNext,
            stepNumber: history.length
        })
        console.log(history)

    }

    jumpto(step) {
        this.setState(
            {
                stepNumber: step,
                xNext: (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 historyMove = move ?
                'go to move#' + move :
                `go to Game start`
            return (
                <li key={move}>
                    <button onClick={() => this.jumpto(move)}>
                        {historyMove}
                    </button>
                </li>
            )
        })

        let status;
        if (winner) {
            status = 'Winner: ' + winner;
        } else {
            status = 'Next player: ' + (this.state.xNext ? 'X' : 'O');
        }
        return (
            <div className="game">
                <div className="game-board">
                    <Board
                        onClick={(i) => { this.handleClick(i) }}
                        squares={current.squares} />
                </div>
                <div className="game-info">
                    <div>{status}</div>
                    <ol>{moves}</ol>
                </div>
            </div>
        );
    }
}


ReactDOM.render(
    <Game />,
    document.getElementById('root')
);
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;
}