Function handleChange

examples/00 Chessboard/Tutorial App/index.js:14–21

(knightPosition)

  }

  handleChange(knightPosition) {
    const nextState = { knightPosition };
    if (this.state) {
      this.setState(nextState);
    } else {
      this.state = nextState;
    }
  }

  componentWillUnmount() {
    this.unobserve();