Javascript 如何使用react钩子有条件地重置状态计数
用户提交我的表单后,Javascript 如何使用react钩子有条件地重置状态计数,javascript,reactjs,react-hooks,next.js,Javascript,Reactjs,React Hooks,Next.js,用户提交我的表单后,handleSubmit函数运行并统计类名中包含“show”的li元素的数量,显示所有搜索结果。它用setStoreCount(prevCount=>prevCount+1)将这些计数相加,然后我更新了我的FAQ{searchCount}UI,其中显示了搜索结果的数量 useEffect(() => { setSearchCount(storeCount) // collect all storeCount }, [storeCount]) 问题是:假设第一次搜索
handleSubmit
函数运行并统计类名中包含“show”的li
元素的数量,显示所有搜索结果。它用setStoreCount(prevCount=>prevCount+1)将这些计数相加
,然后我更新了我的FAQ{searchCount}
UI,其中显示了搜索结果的数量
useEffect(() => {
setSearchCount(storeCount) // collect all storeCount
}, [storeCount])
问题是:假设第一次搜索得到5个结果
然后UI将显示FAQ 5
。如果再次搜索相同的内容,您仍然会得到5个结果,并且希望UI仍然显示FAQ 5
,但是因为storeCount
无法重置为0
,它会显示FAQ 10
(5+5),然后显示FAQ 15
(5+5+5)等等
因为每当storeCount
更改时,我的useEffect都会有条件地运行,所以我无法将其重置为0,因为这样我将始终显示FAQ 0
在下面的代码中刷新每次搜索的计数时,如何显示搜索结果的数量
import React, { useState, useRef, useEffect } from 'react'
import ContentsWrap from '../../components/contents-wrap'
import FrequentList from './tabs/frequent'
import EstimateList from './tabs/estimate'
import ReturnList from './tabs/return'
import EtcList from './tabs/etc'
import SubsidiaryList from './tabs/subsidiary'
import ServiceList from './tabs/service'
import InList from './tabs/in'
import OutList from './tabs/out'
import styles from './index.module.scss'
export default function FAQ () {
const [tab, setTab] = useState('frequent')
const [storeText, setStoreText] = useState('') // stores searchbar text as user types
const [searchText, setSearchText] = useState('') // sends searchbar text to List component props on form submit
const [storeCount, setStoreCount] = useState(0) // stores count of each li element className that includes 'show'
const [searchCount, setSearchCount] = useState(0) // shows search count in UI
const searchContainer = useRef(null)
const handleSubmit = e => {
e.preventDefault()
setSearchText(storeText)
setTab('all')
setTimeout(() => {
// gets all <ul> children of <div class = "faq-list-wrap">
for (let i = 0; i < searchContainer.current.children.length; i++) {
// gets all <li> children of each <ul>
for (let j = 0; j < searchContainer.current.children[i].children.length; j++) {
// checks if each li class name has 'show'
if (searchContainer.current.children[i].children[j].className.includes('show')) {
console.log('count added')
setStoreCount(prevCount => prevCount + 1)
}
}
}
}, 100) // setTimeOut needed to target searchContainer after search and not before
}
const handleChange = newId => {
setTab(newId)
setStoreText('') // clear input value on tab click
setSearchText('') // show all search items on tab click
}
useEffect(() => {
setSearchCount(storeCount) // collect all storeCount
}, [storeCount])
return (
<ContentsWrap>
<div className="content-wrap content-width">
{/* <!-- S: faq-wrap --> */}
<div className="faq-wrap">
<div className="faq-title-wrap"><h2 className="title">FAQ {searchCount}</h2></div>
<form onSubmit={handleSubmit}>
<input
type="text"
placeholder="Search"
className={styles.searchBox}
value={storeText}
onChange={e => {
setStoreText(e.target.value)
}}
/>
</form>
{/* <!-- S: faq-list-wrap --> */}
<div className="faq-list-wrap" ref={searchContainer} >
{tab === 'all' && (
<>
<FrequentList searchText={searchText} />
<EstimateList searchText={searchText} />
<ReturnList searchText={searchText} />
<EtcList searchText={searchText} />
<SubsidiaryList searchText={searchText} />
<ServiceList searchText={searchText} />
<InList searchText={searchText} />
<OutList searchText={searchText} />
</>
)}
{tab === 'frequent' && (
<FrequentList searchText={searchText}/>
)}
{tab === 'estimate' && (
<EstimateList searchText={searchText}/>
)}
{tab === 'return' && (
<ReturnList searchText={searchText} />
)}
{tab === 'subsidiary' && (
<SubsidiaryList searchText={searchText} />
)}
{tab === 'service' && (
<ServiceList searchText={searchText} />
)}
{tab === 'in' && (
<InList searchText={searchText} />
)}
{tab === 'out' && (
<OutList searchText={searchText} />
)}
{tab === 'etc' && (
<EtcList searchText={searchText} />
)}
</div>
{/* <!-- E: faq-list-wrap --> */}
</div>
{/* <!-- E: faq-wrap --> */}
</div>
</ContentsWrap>
)
}
import React,{useState,useRef,useffect}来自“React”
从“../../components/contents wrap”导入ContentsWrap
从“./tabs/frequent”导入频繁列表
从“./tabs/estimate”导入估算列表
从“./tabs/return”导入ReturnList
从“/tabs/etc”导入EtcList
从“./tabs/SubsidiaryList”导入子目录列表
从“./tabs/service”导入服务列表
从“/tabs/in”导入InList
从“./tabs/out”导入大纲视图
从“./index.module.scss”导入样式
导出默认函数FAQ(){
const[tab,setTab]=useState('frequency')
const[storeText,setStoreText]=useState(“”)//将搜索栏文本存储为用户类型
const[searchText,setSearchText]=useState(“”)//发送搜索栏文本以列出表单提交中的组件道具
const[storeCount,setStoreCount]=useState(0)//存储包含“show”的每个li元素类名的计数
const[searchCount,setSearchCount]=useState(0)//在UI中显示搜索计数
const searchContainer=useRef(null)
常量handleSubmit=e=>{
e、 预防默认值()
setSearchText(storeText)
setTab('all')
设置超时(()=>{
//获取的所有子级
for(设i=0;i
for(设j=0;jprevCount+1)
}
}
}
},100)//setTimeOut需要在搜索之后而不是之前以searchContainer为目标
}
常量handleChange=newId=>{
setTab(newId)
setStoreText(“”)//在单击选项卡时清除输入值
setSearchText(“”)//在单击选项卡时显示所有搜索项
}
useffect(()=>{
setSearchCount(storeCount)//收集所有storeCount
},[storeCount])
返回(
{/* */}
常见问题{searchCount}
{
设置存储文本(如目标值)
}}
/>
{/* */}
{tab==='all'&&(
)}
{tab==='frequency'&&(
)}
{tab==='estimate'&&(
)}
{tab==='return'&&(
)}
{tab==='subsidiary'&&(
)}
{tab==='服务'&&(
)}
{tab==='in'&&(
)}
{tab==='out'&&(
)}
{tab==='etc'&&(
)}
{/* */}
{/* */}
)
}
这里的问题在于您的设置存储计数逻辑
在for
循环的这一行中:
if (searchContainer.current.children[i].children[j].className.includes('show')) {
console.log('count added')
setStoreCount(prevCount => prevCount + 1)
}
它将1添加到prevCount
中,这意味着如果prevCount
为5(这是第一次搜索的结果数,它将1添加到该值中,依此类推
您可以做的是在添加找到的元素数之前重置storeCount
。如下所示:
setTimeout(() => {
setStoreCount(0)
// gets all <ul> children of <div class = "faq-list-wrap">
for (let i = 0; i < searchContainer.current.children.length; i++) {
// gets all <li> children of each <ul>
for (let j = 0; j < searchContainer.current.children[i].children.length; j++) {
// checks if each li class name has 'show'
if (searchContainer.current.children[i].children[j].className.includes('show')) {
console.log('count added')
setStoreCount(prevCount => prevCount + 1)
}
}
}
}, 100) // setTimeOut needed to target searchContainer after search and not before
这里的问题在于设置存储计数逻辑
在for
循环的这一行中:
if (searchContainer.current.children[i].children[j].className.includes('show')) {
console.log('count added')
setStoreCount(prevCount => prevCount + 1)
}
它将1添加到prevCount
中,这意味着如果prevCount
为5(这是第一次搜索的结果数,它将1添加到该值中,依此类推
您可以做的是在添加找到的元素数之前重置storeCount
。如下所示:
setTimeout(() => {
setStoreCount(0)
// gets all <ul> children of <div class = "faq-list-wrap">
for (let i = 0; i < searchContainer.current.children.length; i++) {
// gets all <li> children of each <ul>
for (let j = 0; j < searchContainer.current.children[i].children.length; j++) {
// checks if each li class name has 'show'
if (searchContainer.current.children[i].children[j].className.includes('show')) {
console.log('count added')
setStoreCount(prevCount => prevCount + 1)
}
}
}
}, 100) // setTimeOut needed to target searchContainer after search and not before
您的循环只是不断增加storeCount。您应该在循环开始时在零处启动计数器,然后使用setStoreCount将计数器的最终值分配到storeCount中。您的循环只是不断增加storeCount。您应该在循环开始时在零处启动计数器循环,然后使用setStoreCount将计数器的最终值指定给storeCount