Question

尝试从React示例中实现自定义钩子：https://reactjs.org/docs/hooks-faq.html#how-to-get-the-previous-props-or-state，但出现以下错误：

错误：

Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:
1. You might have mismatching versions of React and the renderer (such as React DOM)
2. You might be breaking the Rules of Hooks
3. You might have more than one copy of React in the same app

当我尝试将其作为自定义钩子useEffect导入时，错误发生在usePrevious。

我尝试了以下操作：验证react-dom和react在同一版本上 react-dom@16.8.5 react@16.8.5

已验证我只有一个版本的React

我也相信代码没有违反任何钩子规则。

也尝试在此处查看有关stackoverflow的相关问题。

代码：

// file: use-previous.js

import { useRef, useEffect} from "React"

export const usePrevious = (value) =>  {

    const ref = useRef();
    useEffect(() => {
      ref.current = value;
    });




    return ref.current;
}

// file: layout.js

import React, { useState, useEffect } from "react"

import Header from "./header/header"

import { useFacetsData } from "../hooks/use-facets-data"
import { usePrevious } from "../hooks/use-previous"


export default ({ children, ...props }) => {

    const [ searchValue, setSearchValue ] = useState("")

    const [ facetsSelected, setFacetsSelected ] = useState([])

    const facets = useFacetsData()


    const oldSearchValue = usePrevious(searchValue)
    // const oldFacetsSelected = usePrevious(facetsSelected)

    useEffect(() => {
        // if new searchvalue or new facetvalue

        // if (searchValue !== oldSearchValue || facetsSelected !== oldFacetsSelected) makeSearch()
    }) 

    function makeSearch() {
        console.log('make search')

        // move to searchpage 
    }

    function handleSearchChange(search) {
        setSearchValue(search)
    }

    function handleFacetChange(facets) {
        setFacetsSelected(facets)
    }   

    return   (
        <div>
            {/* Main sticky header */}
            <Header 
                facets={ facets } 
                onSearchChange={ handleSearchChange } 
                onFacetChange={ handleFacetChange } >
            </Header>

            {/* route content */}
           {React.cloneElement(children, { facets })}
        </div>
    )
}

Answer 1

您在usePrevious挂钩文件中的导入不正确。 useRef和useEffect应该从'react'而不是React导入；

import { useRef, useEffect} from "react"

在Gatsby中反应挂钩：无效的挂钩调用

1 个答案: