Tic Tac Toe

index.html

<div id="errors" style="
  background: #c00;
  color: #fff;
  display: none;
  margin: -20px -20px 20px;
  padding: 20px;
  white-space: pre-wrap;
"></div>
<div id="root"></div>
<script>
window.addEventListener('mousedown', function(e) {
  document.body.classList.add('mouse-navigation');
  document.body.classList.remove('kbd-navigation');
});
window.addEventListener('keydown', function(e) {
  if (e.keyCode === 9) {
    document.body.classList.add('kbd-navigation');
    document.body.classList.remove('mouse-navigation');
  }
});
window.addEventListener('click', function(e) {
  if (e.target.tagName === 'A' && e.target.getAttribute('href') === '#') {
    e.preventDefault();
  }
});
window.onerror = function(message, source, line, col, error) {
  var text = error ? error.stack || error : message + ' (at ' + source + ':' + line + ':' + col + ')';
  errors.textContent += text + '\n';
  errors.style.display = '';
};
console.error = (function(old) {
  return function error() {
    errors.textContent += Array.prototype.slice.call(arguments).join(' ') + '\n';
    errors.style.display = '';
    old.apply(this, arguments);
  }
})(console.error);
</script>

script.babel

Square = ({value, handleClick}) => {
  return <button className="square" onClick={handleClick}>{value}</button>
}
class Board extends React.Component {
  renderSquare(i) {
    return (
      <Square 
        value={this.props.squares[i]} 
        handleClick={() => this.props.handleClick(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>
    );
  }
}

function checkWinStatus(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[b] && squares[b] === squares[c])
      return squares[a];
  }
  return null;
}

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

  handleClick(i) {
    const turn = this.state.turn;
    const history = this.state.history.slice(0, turn + 1);
    const squares = history[turn].squares.slice();
    const winningStatus = checkWinStatus(squares);
    if (winningStatus || squares[i]) return;

    squares[i] = turn % 2 ? "X" : "O";
    
    history.push({squares: squares});
    this.setState({
      turn : turn + 1,
      history : history
    });
  }

  jumpToTurn(i){
    if(this.state.turn + i < 0 || this.state.history.length <= this.state.turn + i) 
      return;
    this.setState({
      turn: this.state.turn + i,
    });
  }
  
  render() {
    const turn = this.state.turn;
    const history = this.state.history;
    const squares = history[turn].squares;
    const winningStatus = checkWinStatus(squares);
    let status = "Next turn is: " + (turn % 2 ? "X" : "O");
    if (winningStatus){
      status = winningStatus + " is the winner!";
    }

    return (
      <div className="game">
        <div className="game-board">
          <Board 
            squares={squares} 
            handleClick={(i) => this.handleClick(i)} 
          />
        </div>
        <div className="game-info">
          <div className="status">{status}</div>
          <button onClick={() => this.jumpToTurn(-1)}>Undo</button>
          <button onClick={() => this.jumpToTurn(1)}>Redo</button>
        </div>
      </div>
    );
  }
}

// ========================================

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

scripts

<script src="https://unpkg.com/react@17/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>

style.css

body {
  font: 14px "Century Gothic", Futura, sans-serif;
  margin: 20px;
}

ol, ul {
  padding-left: 30px;
}

.board-row:after {
  clear: both;
  content: "";
  display: table;
}

.status {
  margin-bottom: 10px;
}

.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;
}

.square:focus {
  outline: none;
}

.kbd-navigation .square:focus {
  background: #ddd;
}

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

.game-info {
  margin-left: 20px;
}

tic-tac-toe.markdown

Tic Tac Toe

A Pen by AlexxThunderr on CodePen.

License.