javascript - ES6 - 警告 : setState(…): Cannot update during an existing state transition

Question

我正在重写一些旧的 ReactJS 代码，但在修复这个错误时遇到了困难(错误在控制台中重复了大约 1700 次，DOM 根本没有呈现):

Warning: setState(...): Cannot update during an existing state transition (such as within render or another component's constructor). Render methods should be a pure function of props and state; constructor side-effects are an anti-pattern, but can be moved to componentWillMount.

我是一个组件，它将它的状态传递给一个应该呈现一些控件的组件。基于点击的控件，状态应该改变，新的控件应该呈现。

所以这是我的容器组件:

class TeaTimer extends Component {
    constructor(props) {
        super(props);
        this.state = {
            count: 120,
            countdownStatus: 'started'
        }
    }

    componentDidUpdate(prevProps, prevState) {
        if (this.state.countdownStatus !== prevState.countdownStatus) {
            switch (this.state.countdownStatus) {
                case 'started':
                    this.startTimer();
                    break;
                case 'stopped':
                    this.setState({count:0});
            }
        }
    }

    componentWillUnmount() {
        clearInterval(this.timer);
        delete this.timer;
    }

    startTimer() {
        this.timer = setInterval(() => {
            let newCount = this.state.count -1;
            this.setState({
                count: newCount >= 0 ? newCount : 0
            });
            if(newCount === 0) {
                this.setState({countdownStatus: 'stopped'});
            }
        }, 1000)
    }

    handleStatusChange(newStatus) {
        this.setState({ countdownStatus: newStatus });
    }

    render() {
        let {count, countdownStatus} = this.state;
        let renderStartStop = () => {
            if (countdownStatus !== 'stopped') {
                return <StartStop countdownStatus={countdownStatus} onStatusChange={this.handleStatusChange()}/>
            } else {
                return <div>This will be the slider form</div>
            }
        };
        return(
            <div className={styles.container}>
                <p>This is the TeaTimer component</p>
                <Clock totalSeconds={count}/>
                {renderStartStop()}
            </div>
        )
    }
}

这是我的控件组件:

class StartStop extends Component {
    constructor(props) {
        super(props);
    }

    onStatusChange(newStatus) {
        return() => {
            this.props.onStatusChange(newStatus);
        }
    }

    render() {
        let {countdownStatus} = this.props;

        let renderStartStopButton = () => {
            if(countdownStatus === 'started') {
                return <button onClick={()=> this.onStatusChange('stopped')}>Reset</button>;
            } else {
                return <button onClick={()=> this.onStatusChange('started')}>Start</button>
            }
        };

        return(
            <div className={styles.tt.Controls}>
                {renderStartStopButton()}
            </div>
        )
    }
}

StartStop.propTypes = {
    countdownStatus: React.PropTypes.string.isRequired,
    onStatusChange: React.PropTypes.func.isRequired
};

对于文字墙，我很抱歉，但我真的无法弄清楚错误的来源 - 因此不知道我可以省略代码的哪一部分。

我已经尝试实现在 seemingly related question 中找到的解决方案，但也无法正常工作。

Answer 1

我认为你在这一行中有错字:

return <StartStop countdownStatus={countdownStatus} onStatusChange={this.handleStatusChange()}/> 

应该是:

return <StartStop countdownStatus={countdownStatus} onStatusChange={() => this.handleStatusChange}/>

您似乎在调用方法 handleStatusChange 而不是将其作为回调传递。