javascript - React 组件循环更新 (GraphQL)

Question

美好的一天! 我不断得到

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.

这看起来很明显，但我看不到组件中的循环。

ComponentWillUpdate() 显示它在短时间内使用相同的 props 和状态调用大量重新渲染。

提前致谢。

src/TitleList.js

class TitleList extends Component {
    constructor(props) {
        super(props)
        this.state = {'items': null}
    }
     onSortEnd = ({oldIndex, newIndex}) => {
        this.setState({
             items: arrayMove(this.state.items, oldIndex, newIndex),
         });
     };
    render() {
        if (this.props.allTitlesQuery && this.props.allTitlesQuery.loading){
            return <div>Loading</div>
        }
        if (this.props.allTitlesQuery && this.props.allTitlesQuery.error) {
            return <div>Error!</div>
        }
        const titlesToRender = this.props.allTitlesQuery.allTitles
        this.setState({'items': titlesToRender})
        return <SortableList
            items={this.state.items}
            onSortEnd={this.onSortEnd}
        />;
    }
}

Answer 1

当您调用 this.setState 时，它​​会再次调用您的渲染。因此，如果您从渲染中调用 setState，它将进入递归循环。

您可以尝试以下操作:-

class TitleList extends Component {
    constructor(props) {
        super(props)
        this.state = {'items': null}
    }
    componentDidMount () {
        this.updateState(props);
    }

    componentWillReceiveProps (nextProps) {
        if (this.props.allTitlesQuery.allTitles !== nextProps.allTitlesQuery.allTitles) {
        this.setState(nextProps);
      }
    }

    updateState (props) {
        this.setState({"items":props.allTitlesQuery.allTitles});
    }

     onSortEnd = ({oldIndex, newIndex}) => {
        this.setState({
             items: arrayMove(this.state.items, oldIndex, newIndex),
         });
     };
    render() {
        if (this.props.allTitlesQuery && this.props.allTitlesQuery.loading){
            return <div>Loading</div>
        }
        if (this.props.allTitlesQuery && this.props.allTitlesQuery.error) {
            return <div>Error!</div>
        }
        return <SortableList
            items={this.state.items}
            onSortEnd={this.onSortEnd}
        />;
    }
}

使用 componentDidMount 方法首次渲染数据，如果数据更改则使用 componentWillReceiveProps 方法更新