javascript - React setState inside componentDidUpdare 导致超出最大更新深度

Question

我得到了

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.

但根据我的阅读，我应该能够在 componentDidMount 中调用 setState 而不会出错。

class MyComponent extends Component {
constructor(props) {
    super(props);
    this.state = {
        matchtedProducts: [],
        products: [],
    }
}
async componentDidMount() {
    try {
        const products = await getProducts()
        this.setState({ products })
    } catch(err) {
        console.log(err)
    }
}

componentDidUpdate() {
    const productColor = this.props.size.trim().toLowerCase()
    const productSize = this.props.color.trim().toLowerCase()
    const matches = []

    this.state.products.map(product => {
        const title = product.title
        const titleSpliitet = title.split(',')

        let color = titleSpliitet[1].trim().toLowerCase()
        let size = titleSpliitet[2].trim().toLowerCase()

        if(color == productColor && size == productSize) {
            matches.push(product)
        }

    })
    this.setState({matchtedProducts: matches})
}
render() {
    return (<div></div>)
}

Answer 1

发生这种情况是因为每个 setState 都会触发渲染，然后再次触发 componentDidMount，这基本上会导致无限循环。要停止该循环，您需要设置一些条件，以防止再次渲染，例如

    componentDidUpdate(previousProps, previousState) {
    if (previousProps.data !== this.props.data) {
        this.setState({/*....*/})
    }
   }