Maximum update depth exceeded. This can happen when a component repeatedly calls setState inside componentWillUpdate or componentDidUpdate

UWGOOSE picture UWGOOSE · Mar 11, 2018 · Viewed 17k times · Source

I'm making this Conway's game of life react project and it was working just fine but when I added the last couple of buttons to clear the board and some other functionalities react gave me this error

Maximum update depth exceeded. This can happen when a component 
repeatedly calls setState inside componentWillUpdate or 
componentDidUpdate. React limits the number of nested updates to 
prevent infinite loops. 

From the code snippets it's been showing me it seems that the clear() function is the problem here, but I don't think I did set state inside a render() to trigger an infinite loop. Here are all the code for the clear and componentDidMount, I don't have a componentWillUpdate or componentDidUpdate in my app.

the clear() and Play function in the main class

EDIT 1 : It's telling me that there's something wrong with the setState inside the play() function, however, I always implemented the play function this way and it was always working since the beginning....

clear = ()=>{
    var g = Array(this.rows).fill().map(()=> Array(this.cols).fill(false));

    this.setState({
        generations:0,
        fullGrid: g
    })
}

.....

play = () => {

    let g1 = this.state.fullGrid;
    let g2 = arrayClone(this.state.fullGrid);

    for (let i = 0; i < this.rows; i++) {
        for (let j = 0; j < this.cols; j++) {
            let count = 0;

            if (i > 0)
                if (g1[i - 1][j]) count++;
            if (i > 0 && j > 0)
                if (g1[i - 1][j - 1]) count++;
            if (i > 0 && j < this.cols - 1)
                if (g1[i - 1][j + 1]) count++;
            if (j < this.cols - 1)
                if (g1[i][j + 1]) count++;
            if (j > 0)
                if (g1[i][j - 1]) count++;
            if (i < this.rows - 1)
                if (g1[i + 1][j]) count++;
            if (i < this.rows - 1 && j > 0)
                if (g1[i + 1][j - 1]) count++;
            if (i < this.rows - 1 && this.cols - 1)
                if (g1[i + 1][j + 1]) count++;
            if (g1[i][j] && (count < 2 || count > 3)) g2[i][j] = false;
            if (!g1[i][j] && count === 3) g2[i][j] = true;
        }
    }

    this.setState({
        fullGrid: g2,
        generations: this.state.generations + 1
    });

}


playButton = ()=>{
    clearInterval(this.intervalId);
    this.intervalId = setInterval(this.play, this.speed);
}

pauseButton = ()=>{
    clearInterval(this.intervalId);
}

slow = ()=>{
    this.speed = 1000;
    this.playButton();
}

fast = ()=>{
    this.speed = 100;
    this.playButton();
}

clear = ()=>{
    var g = Array(this.rows).fill().map(()=> Array(this.cols).fill(false))

    this.setState({
        generations:0,
        fullGrid: g
    })
}

The Button Class

class Buttons extends React.Component{

handleSelect = (evt) =>{
    this.props.gridSize(evt);
}

render(){
    return (
        <div className="center">
            <ButtonToolbar>
                <button className='btn btn-info'  onClick={this.props.playButton}>
                    PLAY
                </button>
                <button className='btn btn-info'  onClick={this.props.pauseButton}>
                    PAUSE
                </button>
                <button className='btn btn-info'  onClick={this.props.clear}>
                    CLEAR
                </button>
                <button className='btn btn-info'  onClick={this.props.slow}>
                    SLOW
                </button>
                <button className='btn btn-info'  onClick={this.props.fast}>
                    FAST
                </button>
                <button className='btn btn-info'  onClick={this.props.seed}>
                    SEED
                </button>
                <DropdownButton
                    title="Grid Size"
                    id="size-menu"
                    onSelect={this.handleSelect}
                >
                    <MenuItem eventKey="1">20x10</MenuItem>
                    <MenuItem eventKey="2">50x30</MenuItem>
                    <MenuItem eventKey="3">70x50</MenuItem>
                </DropdownButton>
            </ButtonToolbar>
        </div>
    )
}

}

Answer

Sean picture Sean · Mar 11, 2018

Your onClick handlers are being called continuously. Change them to functions that return the function you wish to call and this should fix your issue.

Example:

<button className='btn btn-info'  onClick={() => this.props.playButton}>
    PLAY
</button>