how to update score dynamicaly in react

Question

I am trying to update my score by calling this.setState({player1: this.state.player1 + 1}).

But it does not allow me to do so. It says that i should do it outside the render method. Can anyone tell me how to do it?

The problem is on the render method in Board component, when i am checking the winner.

I am sorry if i am not precise. This is my first time trying to as a question.

    function Square(props) {
      return (
        <button className="square" onClick={() => props.onClick()}>
          {props.value}
        </button>
      );
    }

    class Board extends React.Component {
      constructor(props) {
        super(props);
        this.state = {
          squares: Array(9).fill(null),
          xIsNext: true,
          player1: 0,
          player2: 0
        };
      }

      handleClick(i) {
        const squares = this.state.squares.slice();
        if (calculateWinner(squares) || squares[i]) {
          return;
        }
        squares[i] = this.state.xIsNext ? "X" : "O";
        this.setState({ squares, xIsNext: !this.state.xIsNext });
      }

      renderSquare(i) {
        return (
          <Square
            value={this.state.squares[i]}
            onClick={() => this.handleClick(i)}
          />
        );
      }

      deleteBoard = () => {
        let squares = this.state.squares.slice();
        squares = Array(9).fill(null);
        this.setState({ squares, xIsNext: true });
      };

      render() {
        const winner = calculateWinner(this.state.squares);
        let status;
        if (winner) {
          status = "Winner: " + winner; 
//if(winner === 'X'){this.setState({player1: this.state.player1 + 1})}
        } else {
          status = "Next player: " + (this.state.xIsNext ? "X" : "O");
        }

        return (
          <div>
            <div className="status">{status}</div>
            <div>
              <button onClick={() => this.deleteBoard()}>Start over </button>{" "}
            </div>
            <div>Player1 {this.state.player1} </div>
            <div>Player2 {this.state.player2} </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 {
      render() {
        return (
          <div className="game">
            <div className="game-board">
              <Board />
            </div>
            <div className="game-info">
              <div>{/* status */}</div>
              <ol>{/* TODO */}</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;
    }

Possible duplicate of [Calling setState in render is not avoidable](https://stackoverflow.com/questions/35290245/calling-setstate-in-render-is-not-avoidable) — akosel, Sep 19 '18 at 00:21
You can't call `setState()` in `render()`, because `setState()` triggers a re-render, so you'll go into an infinite loop. The logical choice it to check for a winner when they make a move, then handle it there. (`handleClick()` looks like the move handling function, though I only had a brief look over the code) — Jayce444, Sep 19 '18 at 00:22
A good choice if you don't want to put it in the handleClick is to use componentDidUpdate() which can let you know when this.state.squares changes and you can call calculateWinner there — schlaegerz, Sep 19 '18 at 00:51

score 0 · Answer 1 · answered Sep 19 '18 at 00:52

0

You can't call setState in render since it triggers a re-render infinite loop.

Looks like you're already calculating the winner on every handleClick so you could setState in the calculateWinner function.

answered Sep 19 '18 at 00:52

Andy Mai

84
5

how to update score dynamicaly in react

1 Answers1