react Game: Tic Tac Toe

* Board.js

import React from 'react';

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-new">
                    {this.renderSquare(0)}
                    {this.renderSquare(1)}
                    {this.renderSquare(2)}
                </div>
                <div className="board-new">
                    {this.renderSquare(3)}
                    {this.renderSquare(4)}
                    {this.renderSquare(5)}
                </div>
                <div className="board-new">
                    {this.renderSquare(6)}
                    {this.renderSquare(7)}
                    {this.renderSquare(8)}
                </div>
            </div>
        )
    }
}

class Square extends React.Component {

    render() {
        return (
            <button
                className="square"
                onClick={this.props.onClick}>
                {this.props.value}
            </button>
        )
    }
}

export default Board;

* Game.js

import React from 'react';
import Board from "./Board";

class Game extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            history: [{
                squares: Array(9).fill(null),
            }],
            stepNumber: 0,
            xIsNext: true,
        };
    }

    jumpTo(step) {
        this.setState({
            stepNumber: step,
            xIsNext: (step % 2) === 0,
        })
    }

    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,
        })
    }

    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 (
                <li>
                    <button onClick={()=>this.jumpTo(move)}>{desc}</button>
                </li>
            );
        });

        let status;
        if (winner) {
            status = 'Winner: ' + winner;
        } else {
            status = 'Next player: ' + (this.state.xIsNext ? 'X':'O');
        }

        return (
            <div className="game">
                <div className="game-board">
                    <Board
                        squares={current.squares}
                        onClick={(i) => this.handleClick(i)}
                    />
                </div>
                <div className="game-info">
                    <div>{status}</div>
                    <ol>{moves}</ol>
                </div>
            </div>
        );
    }

}

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;
}

export default Game;

* index.css

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New",
    monospace;
}

button, hr, input {
  overflow: visible;
}

button, input, optgroup, select, textarea {
  font-family: sans-serif;
  font-size: 100%;
  line-height: 1.15;
  margin: 0;
}

button, select {
  text-transform: none;
}

#root {
  padding: 20px 40px;
}

.game {
  display: flex;
  flex-direction: row;
}


.game-info {
  margin-left: 20px;
}
.board-row:after {
  clear: both;
  content: "";
  display: table;
}

.square {
  background: #fff;
  border: 1px solid #999;
  float: left;
  font-size: 24px;
  font-weight: bold;
  line-height: 34px;
  height: 34px;
  margin-right: -1px;
  margin-top: -1px;
  padding: 0;
  text-align: center;
  width: 34px;
}

* index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
// import App from './App';
import Game from './Game';
import * as serviceWorker from './serviceWorker';

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

// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();

* run:

npm start

 

参考文档: https://reactjs.org/tutorial/tutorial.html#help-im-stuck

1. Display the location for each move in the format (col, row) in the move history list.
2. Bold the currently selected item in the move list.
3. Rewrite Board to use two loops to make the squares instead of hardcoding them.
4. Add a toggle button that lets you sort the moves in either ascending or descending order.
5. When someone wins, highlight the three squares that caused the win.
6. When no one wins, display a message about the result being a draw.