Javascript 防止复选框在React中重新呈现
我试图基于动态返回数据呈现多个复选框,并将其选中状态存储在本地状态中 但是,当生成更多的复选框时,性能开始下降。我注意到这个问题是由于每当选中任何一个复选框时,都会不断地重新呈现所有复选框(复选框状态都存储在具有不同键的同一对象中) 这是我的示例代码和codesandbox链接,用于查看实际性能问题(请注意选中复选框时的延迟)Javascript 防止复选框在React中重新呈现,javascript,reactjs,checkbox,react-hooks,Javascript,Reactjs,Checkbox,React Hooks,我试图基于动态返回数据呈现多个复选框,并将其选中状态存储在本地状态中 但是,当生成更多的复选框时,性能开始下降。我注意到这个问题是由于每当选中任何一个复选框时,都会不断地重新呈现所有复选框(复选框状态都存储在具有不同键的同一对象中) 这是我的示例代码和codesandbox链接,用于查看实际性能问题(请注意选中复选框时的延迟) 导出默认函数App(){ const[checkboxResponse,setCheckboxResponse]=useState([]); const[checkbox
导出默认函数App(){
const[checkboxResponse,setCheckboxResponse]=useState([]);
const[checkboxList,setCheckboxList]=useState();
const[checkboxStates,setCheckboxStates]=useState({});
useffect(()=>{
//生成虚拟数据
常量dummyData=[];
for(设i=0;i<1000;i++){
dummyData.push(i.toString());
}
//将dummyData设置为动态数据复选框
setCheckboxResponse(dummyData);
}, []);
useffect(()=>{
//单击复选框后,添加到本地复选框状态对象
const checkboxChange=key=>event=>{
SetCheckBoxState({…CheckBoxState,[key]:event.target.checked});
};
//检查数据是否可用
如果(复选框响应){
const checkbox=checkboxResponse.map(键=>{
const value=checkboxStates[key]?checkboxStates[key]:false;
//渲染复选框
返回(
);
});
设置复选框列表(复选框);
}
},[checkboxResponse,CheckBoxState]);
返回(
{复选框列表}
);
}
似乎每当更改checkboxStates
时,就会重新运行useffect
钩子,再次触发所有复选框的重新渲染
是否可以防止React在状态更改时再次重新呈现所有复选框?还是我们必须为每个复选框动态创建一个单独的状态
任何帮助都将不胜感激。您可以使用
React.memo
防止重新呈现未更改的复选框。像这样:
import React, { useState, useEffect } from "react";
import { Checkbox, FormControlLabel } from "@material-ui/core";
import "./styles.css";
export default function App() {
const [checkboxResponse, setCheckboxResponse] = useState([]);
const [checkboxStates, setCheckboxStates] = useState({});
//When checkbox is clicked, add to local checkbox states object
const checkboxChange = key => event => {
setCheckboxStates({ ...checkboxStates, [key]: event.target.checked });
};
useEffect(() => {
//Generate dummy data
const dummyData = [];
for (let i = 0; i < 1000; i++) {
dummyData.push(i.toString());
}
//Set dummyData as checkbox dynamic data
setCheckboxResponse(dummyData);
}, []);
return (
<div className="App">
{checkboxResponse.map(key => {
const value = checkboxStates[key] ? checkboxStates[key] : false;
//Render checkbox
return (
<FormControlLabel
key={key}
checked={value}
control={<MemoCheckbox key={key} checkboxChange={checkboxChange} />}
label={key}
/>
);
})}
</div>
);
}
const CustomCheckbox = ({ key, checkboxChange }) => (
<Checkbox size="small" value={key} onChange={checkboxChange(key)} />
);
const MemoCheckbox = React.memo(
CustomCheckbox,
(prev, next) => prev.key === next.key
);
import React,{useState,useffect}来自“React”;
从“@material ui/core”导入{Checkbox,FormControlLabel};
导入“/styles.css”;
导出默认函数App(){
const[checkboxResponse,setCheckboxResponse]=useState([]);
const[checkboxStates,setCheckboxStates]=useState({});
//单击复选框后,添加到本地复选框状态对象
const checkboxChange=key=>event=>{
SetCheckBoxState({…CheckBoxState,[key]:event.target.checked});
};
useffect(()=>{
//生成虚拟数据
常量dummyData=[];
for(设i=0;i<1000;i++){
dummyData.push(i.toString());
}
//将dummyData设置为动态数据复选框
setCheckboxResponse(dummyData);
}, []);
返回(
{checkboxResponse.map(键=>{
const value=checkboxStates[key]?checkboxStates[key]:false;
//渲染复选框
返回(
);
})}
);
}
const CustomCheckbox=({key,checkboxChange})=>(
);
const MemoCheckbox=React.memo(
自定义复选框,
(上一个,下一个)=>prev.key===next.key
);
但是,它可能仍然不够快,因为当您单击复选框时,它仍然通过.map
循环并创建元素
这是备忘录
import React, { useState, useEffect } from "react";
import { Checkbox, FormControlLabel } from "@material-ui/core";
import "./styles.css";
export default function App() {
const [checkboxResponse, setCheckboxResponse] = useState([]);
const [checkboxStates, setCheckboxStates] = useState({});
//When checkbox is clicked, add to local checkbox states object
const checkboxChange = key => event => {
setCheckboxStates({ ...checkboxStates, [key]: event.target.checked });
};
useEffect(() => {
//Generate dummy data
const dummyData = [];
for (let i = 0; i < 1000; i++) {
dummyData.push(i.toString());
}
//Set dummyData as checkbox dynamic data
setCheckboxResponse(dummyData);
}, []);
return (
<div className="App">
{checkboxResponse.map(key => {
const value = checkboxStates[key] ? checkboxStates[key] : false;
//Render checkbox
return (
<FormControlLabel
key={key}
checked={value}
control={<MemoCheckbox key={key} checkboxChange={checkboxChange} />}
label={key}
/>
);
})}
</div>
);
}
const CustomCheckbox = ({ key, checkboxChange }) => (
<Checkbox size="small" value={key} onChange={checkboxChange(key)} />
);
const MemoCheckbox = React.memo(
CustomCheckbox,
(prev, next) => prev.key === next.key
);