{"id":7054,"date":"2023-09-15T17:19:56","date_gmt":"2023-09-15T09:19:56","guid":{"rendered":"https:\/\/i007.vip:15443\/wordpress\/?p=7054"},"modified":"2023-09-15T17:19:56","modified_gmt":"2023-09-15T09:19:56","slug":"react-hook%e4%b9%8busestate%ef%bc%8cuseeffect%e7%b2%be%e8%ae%b2","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/7054","title":{"rendered":"React\u2014\u2014hook\u4e4buseState\uff0cuseEffect\u7cbe\u8bb2"},"content":{"rendered":"

cc from<\/a><\/p>\n

 <\/p>\n

Mr.\u6307\u5c16\u821e\u8005<\/p>\n

\u5df2\u4e8e 2022-06-15 14:53:17 \u4fee\u6539<\/p>\n

2091
\n\u6536\u85cf 7
\n\u5206\u7c7b\u4e13\u680f\uff1a React \u6587\u7ae0\u6807\u7b7e\uff1a react.js \u524d\u7aef reactjs
\n\u7248\u6743<\/p>\n

React
\n\u4e13\u680f\u6536\u5f55\u8be5\u5185\u5bb9
\n14 \u7bc7\u6587\u7ae03 \u8ba2\u9605
\n\u8ba2\u9605\u4e13\u680f
\nhook\u662f\u4ec0\u4e48\uff1f
\n\u51fd\u6570\u5f0f\u7ec4\u4ef6+hook<\/p>\n

Hook \u662f\u4e00\u4e9b\u53ef\u4ee5\u8ba9\u4f60\u5728\u51fd\u6570\u7ec4\u4ef6\u91cc\u201c\u94a9\u5165\u201d React state \u53ca\u751f\u547d\u5468\u671f\u7b49\u7279\u6027\u7684\u51fd\u6570\u3002Hook \u4e0d\u80fd\u5728 class \u7ec4\u4ef6\u4e2d\u4f7f\u7528 \u2014\u2014 \u8fd9\u4f7f\u5f97\u4f60\u4e0d\u4f7f\u7528 class \u4e5f\u80fd\u4f7f\u7528 React\u3002<\/p>\n

React \u5185\u7f6e\u4e86\u4e00\u4e9b\u50cf useState \u8fd9\u6837\u7684 Hook\u3002\u4f60\u4e5f\u53ef\u4ee5\u521b\u5efa\u4f60\u81ea\u5df1\u7684 Hook \u6765\u590d\u7528\u4e0d\u540c\u7ec4\u4ef6\u4e4b\u95f4\u7684\u72b6\u6001\u903b\u8f91\u3002<\/p>\n

\u4e00\uff0cState Hook
\n\u5148\u770b\u4e00\u4e0b\u4f7f\u7528\u4ee3\u7801\uff1a\u5b9e\u73b0\u4e00\u4e2a\u57fa\u672c\u7684\u8ba1\u6570\u5668<\/p>\n

\u7b2c\u4e00\u884c: \u5f15\u5165 React \u4e2d\u7684 useState Hook\u3002\u5b83\u8ba9\u6211\u4eec\u5728\u51fd\u6570\u7ec4\u4ef6\u4e2d\u5b58\u50a8\u5185\u90e8 state\u3002
\n\u7b2c\u4e09\u884c: \u5728 App\u7ec4\u4ef6\u5185\u90e8\uff0c\u6211\u4eec\u901a\u8fc7\u8c03\u7528 useState Hook \u58f0\u660e\u4e86\u4e00\u4e2a\u65b0\u7684 state \u53d8\u91cf\u3002\u5b83\u8fd4\u56de\u4e00\u5bf9\u503c\u7ed9\u5230\u6211\u4eec\u547d\u540d\u7684\u53d8\u91cf\u4e0a\u3002\u6211\u4eec\u628a\u53d8\u91cf\u547d\u540d\u4e3a count\uff0c\u56e0\u4e3a\u5b83\u5b58\u50a8\u7684\u662f\u70b9\u51fb\u6b21\u6570\u3002\u6211\u4eec\u901a\u8fc7\u4f20 0 \u4f5c\u4e3a useState \u552f\u4e00\u7684\u53c2\u6570\u6765\u5c06\u5176\u521d\u59cb\u5316\u4e3a 0\u3002\u7b2c\u4e8c\u4e2a\u8fd4\u56de\u7684\u503c\u672c\u8eab\u5c31\u662f\u4e00\u4e2a\u51fd\u6570\u3002\u5b83\u8ba9\u6211\u4eec\u53ef\u4ee5\u66f4\u65b0 count \u7684\u503c\uff0c\u6240\u4ee5\u6211\u4eec\u53eb\u5b83 setCount\u3002
\n\u7b2c\u4e03\u884c: \u5f53\u7528\u6237\u70b9\u51fb\u6309\u94ae\u540e\uff0c\u6211\u4eec\u4f20\u9012\u4e00\u4e2a\u65b0\u7684\u503c\u7ed9 setCount\u3002React \u4f1a\u91cd\u65b0\u6e32\u67d3 App \u7ec4\u4ef6\uff0c\u5e76\u628a\u6700\u65b0\u7684 count \u4f20\u7ed9\u5b83\u3002
\nimport React,{useState} from ‘react’
\nfunction App(){
\n\/\/\u58f0\u660e\u4e00\u4e2a\u53ebcount\u7684state\u53d8\u91cf
\n\/\/ \u4f7f\u7528\u6570\u7ec4\u89e3\u6784\u7684\u8bed\u6cd5\uff0c\u8ba9\u6211\u4eec\u5728\u8c03\u7528userState\u7684\u65f6\u5019\u7ed9state\u53d8\u91cf\u53d6\u4e0d\u540c\u7684\u540d\u5b57
\nconst [count,setCount]=useState(12)
\nreturn(
\n<>
\n<p>{count}<\/p>
\n<button onClick={()=>setCount(count+1)}>\u70b9\u6211\u4e00\u4e0b<\/button>
\n<\/>
\n)
\n}<\/p>\n

export default App
\n\u901a\u4fd7\u7684\u8bb2\uff1a\u7ec4\u4ef6\u7684\u66f4\u65b0\u5206\u4e3a\u4e24\u4e2a\u8fc7\u7a0b
\n\u9996\u6b21\u6e32\u67d3\u65f6\uff0c\u7ec4\u4ef6\u5185\u90e8\u4ee3\u7801\u4f1a\u88ab\u6267\u884c\u4e00\u6b21\uff0c\u5176\u4e2duseState\u4e5f\u4f1a\u88ab\u6267\u884c\uff0c\u91cd\u70b9\u6ce8\u610f\uff1a\u521d\u59cb\u503c\u53ea\u6709\u5728\u9996\u6b21\u6e32\u67d3\u65f6\u751f\u6548<\/p>\n

\u66f4\u65b0\u6e32\u67d3\uff1asetcount\u4e5f\u4f1a\u66f4\u65b0\uff0c<\/p>\n

1.\u7ec4\u4ef6App\u4f1a\u518d\u6b21\u6e32\u67d3\uff0c\u8fd9\u4e2a\u51fd\u6570\u4f1a\u518d\u6b21\u6267\u884c<\/p>\n

2.useState\u518d\u6b21\u6267\u884c\u65f6\uff0c\u5f97\u5230\u7684\u65b0\u7684count\u4e0d\u662f0\u800c\u662f\u65b0\u4fee\u6539\u76841\uff0c\u6a21\u677f\u4f1a\u7528\u65b0\u503c\u6e32\u67d3<\/p>\n

\u6ce8\u610f\uff1a\u4e0d\u80fd\u5199count++\u6216count–;\u5199\u6210count+1;\u6216\u8005count-1<\/p>\n

\u5728\u8c03\u7528useState()\u65f6\u90fd\u505a\u4e86\u4ec0\u4e48\uff1f
\n\u5b83\u5b9a\u4e49\u4e00\u4e2a \u201cstate \u53d8\u91cf\u201d\u3002\u6211\u4eec\u7684\u53d8\u91cf\u53eb count\uff0c \u4f46\u662f\u6211\u4eec\u53ef\u4ee5\u53eb\u4ed6\u4efb\u4f55\u540d\u5b57\uff0c\u6bd4\u5982 banana\u3002\u8fd9\u662f\u4e00\u79cd\u5728\u51fd\u6570\u8c03\u7528\u65f6\u4fdd\u5b58\u53d8\u91cf\u7684\u65b9\u5f0f \u2014\u2014 useState \u662f\u4e00\u79cd\u65b0\u65b9\u6cd5\uff0c\u5b83\u4e0e class \u91cc\u9762\u7684 this.state \u63d0\u4f9b\u7684\u529f\u80fd\u5b8c\u5168\u76f8\u540c\u3002\u4e00\u822c\u6765\u8bf4\uff0c\u5728\u51fd\u6570\u9000\u51fa\u540e\u53d8\u91cf\u5c31\u4f1a\u201d\u6d88\u5931\u201d\uff0c\u800c state \u4e2d\u7684\u53d8\u91cf\u4f1a\u88ab React \u4fdd\u7559<\/p>\n

useState \u9700\u8981\u54ea\u4e9b\u53c2\u6570\uff1f
\nuseState() \u65b9\u6cd5\u91cc\u9762\u552f\u4e00\u7684\u53c2\u6570\u5c31\u662f\u521d\u59cb state\u3002\u4e0d\u540c\u4e8e class \u7684\u662f\uff0c\u6211\u4eec\u53ef\u4ee5\u6309\u7167\u9700\u8981\u4f7f\u7528\u6570\u5b57\u6216\u5b57\u7b26\u4e32\u5bf9\u5176\u8fdb\u884c\u8d4b\u503c\uff0c\u800c\u4e0d\u4e00\u5b9a\u662f\u5bf9\u8c61\u3002\u5728\u793a\u4f8b\u4e2d\uff0c\u53ea\u9700\u4f7f\u7528\u6570\u5b57\u6765\u8bb0\u5f55\u7528\u6237\u70b9\u51fb\u6b21\u6570\uff0c\u6240\u4ee5\u6211\u4eec\u4f20\u4e86 0 \u4f5c\u4e3a\u53d8\u91cf\u7684\u521d\u59cb state\u3002\uff08\u5982\u679c\u6211\u4eec\u60f3\u8981\u5728 state \u4e2d\u5b58\u50a8\u4e24\u4e2a\u4e0d\u540c\u7684\u53d8\u91cf\uff0c\u53ea\u9700\u8c03\u7528 useState() \u4e24\u6b21\u5373\u53ef\u3002\uff09<\/p>\n

useState \u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u662f\u4ec0\u4e48\uff1f
\n\u8fd4\u56de\u503c\u4e3a\uff1a\u5f53\u524d state \u4ee5\u53ca\u66f4\u65b0 state \u7684\u51fd\u6570\u3002\u8fd9\u5c31\u662f\u6211\u4eec\u5199 const [count, setCount] = useState() \u7684\u539f\u56e0\u3002\u8fd9\u4e0e class \u91cc\u9762 this.state.count \u548c this.setState \u7c7b\u4f3c\uff0c\u552f\u4e00\u533a\u522b\u5c31\u662f\u4f60\u9700\u8981\u6210\u5bf9\u7684\u83b7\u53d6\u5b83\u4eec\u3002<\/p>\n

\u65b9\u62ec\u53f7\u6709\u4ec0\u4e48\u7528\uff1f
\n\u8fd9\u79cd JavaScript \u8bed\u6cd5\u53eb\u6570\u7ec4\u89e3\u6784\u3002\u5b83\u610f\u5473\u7740\u6211\u4eec\u540c\u65f6\u521b\u5efa\u4e86 count \u548c setCount \u4e24\u4e2a\u53d8\u91cf\uff0ccount \u7684\u503c\u4e3a useState \u8fd4\u56de\u7684\u7b2c\u4e00\u4e2a\u503c\uff0csetCount \u662f\u8fd4\u56de\u7684\u7b2c\u4e8c\u4e2a\u503c\u3002\u5b83\u7b49\u4ef7\u4e8e\u4e0b\u9762\u7684\u4ee3\u7801\uff1a<\/p>\n

var fruitStateVariable = useState(‘banana’); \/\/ \u8fd4\u56de\u4e00\u4e2a\u6709\u4e24\u4e2a\u5143\u7d20\u7684\u6570\u7ec4
\nvar fruit = fruitStateVariable[0]; \/\/ \u6570\u7ec4\u91cc\u7684\u7b2c\u4e00\u4e2a\u503c
\nvar setFruit = fruitStateVariable[1]; \/\/ \u6570\u7ec4\u91cc\u7684\u7b2c\u4e8c\u4e2a\u503c
\n\u5f53\u6211\u4eec\u4f7f\u7528 useState \u5b9a\u4e49 state \u53d8\u91cf\u65f6\u5019\uff0c\u5b83\u8fd4\u56de\u4e00\u4e2a\u6709\u4e24\u4e2a\u503c\u7684\u6570\u7ec4\u3002\u7b2c\u4e00\u4e2a\u503c\u662f\u5f53\u524d\u7684 state\uff0c\u7b2c\u4e8c\u4e2a\u503c\u662f\u66f4\u65b0 state \u7684\u51fd\u6570\u3002\u4f7f\u7528 [0] \u548c [1] \u6765\u8bbf\u95ee<\/p>\n

\u6ce8\u610f\uff1a\u6570\u7ec4\u4e2d\u540d\u5b57\u53ef\u4ee5\u6539\u53d8\uff0c\u987a\u5e8f\u4e0d\u53ef\u4ee5\u6539\u53d8<\/p>\n

\u4e8c\uff0cuseEffect
\n1.\u57fa\u672c\u4f7f\u7528
\nEffect Hook \u53ef\u4ee5\u8ba9\u4f60\u5728\u51fd\u6570\u7ec4\u4ef6\u4e2d\u6267\u884c\u526f\u4f5c\u7528\u64cd\u4f5c<\/p>\n

\u90a3\u4e48\u4ec0\u4e48\u662f\u526f\u4f5c\u7528\u5462\uff1f
\n\u6570\u636e\u83b7\u53d6\uff0c\u8bbe\u7f6e\u8ba2\u9605\u4ee5\u53ca\u624b\u52a8\u66f4\u6539 React \u7ec4\u4ef6\u4e2d\u7684 DOM \u90fd\u5c5e\u4e8e\u526f\u4f5c\u7528\u3002
\n\u5148\u770b\u4e00\u6bb5\u57fa\u672c\u4f7f\u7528\u7684\u4ee3\u7801<\/p>\n

\u70b9\u51fb\u8ba1\u6570\u5668\uff0c\u5728title\u6807\u7b7e\u680f\u540c\u6b65\u663e\u793a\u8ba1\u6570\u7ed3\u679c<\/p>\n

import React,{useState,useEffect} from ‘react’<\/p>\n

function App(){
\nconst [count,setCount]=useState(1)
\nuseEffect(()=>{
\ndocument.title=count
\n})
\nreturn(
\n<><\/p>\n

<p>{count}<\/p>
\n<button onClick={()=>setCount(count+1)}>\u70b9\u6211\u4e00\u4e0b<\/button>
\n<\/>
\n)<\/p>\n

}<\/p>\n

export default App
\n\u5982\u679c\u4f60\u770b\u61c2\u4e86\u4e0a\u9762\u4ee3\u7801\uff0c\u719f\u6089\u751f\u547d\u5468\u671f\u51fd\u6570\u7684\u8bdd\u5c31\u4f1a\u53d1\u73b0<\/p>\n

useEffect Hook \u770b\u505a componentDidMount\uff0ccomponentDidUpdate \u548c componentWillUnmount \u8fd9\u4e09\u4e2a\u51fd\u6570\u7684\u7ec4\u5408\u3002<\/p>\n

class Example extends React.Component {
\nconstructor(props) {
\nsuper(props);
\nthis.state = {
\ncount: 0
\n};
\n}<\/p>\n

componentDidMount() {
\ndocument.title = `You clicked ${this.state.count} times`;
\n}
\ncomponentDidUpdate() {
\ndocument.title = `You clicked ${this.state.count} times`;
\n}<\/p>\n

render() {
\nreturn (
\n<div>
\n<p>You clicked {this.state.count} times<\/p>
\n<button onClick={() => this.setState({ count: this.state.count + 1 })}>
\nClick me
\n<\/button>
\n<\/div>
\n);
\n}
\n}
\n\u6ce8\u610f\uff1a\u8fd9\u6837\u6211\u4eec\u5c31\u8981\u5728\u4e24\u4e2a\u751f\u547d\u5468\u671f\u4e2d\u5199\u540c\u6837\u7684\u4ee3\u7801\uff0c\u5c31\u7b97\u5c01\u88c5\u6210\u51fd\u6570\uff0c\u4e5f\u5f97\u8c03\u7528\u4e24\u6b21<\/p>\n

\u8fd9\u4e2a\u65f6\u5019\u4f60\u56de\u8fc7\u5934\u770b\u770b\u6700\u521d\u4f7f\u7528useEffect\u7684\u4ee3\u7801<\/p>\n

2.\u4f9d\u8d56\u7279\u5b9a\u9879
\n\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u6bcf\u6b21\u6e32\u67d3\u540e\u90fd\u6267\u884c\u6e05\u7406\u6216\u8005\u6267\u884c effect \u53ef\u80fd\u4f1a\u5bfc\u81f4\u6027\u80fd\u95ee\u9898\u3002<\/p>\n

\u7ed9userEffect(),\u4f20\u5165\u7b2c\u4e8c\u4e2a\u53c2\u6570\uff0c\u7279\u5b9a\u6570\u636e\u8fdb\u884c\u8c03\u7528<\/p>\n

\u5982\u4e0b\u4ee3\u7801\uff0c\u5b9a\u4e49\u4e24\u4e2a\u8ba1\u6570\u5668\u4f7f\u7528\u7b2c\u4e00\u4e2a\u8fdb\u884c\u7279\u5b9a\u4f9d\u8d56\u4f20\u5165\uff0c\u7b2c\u4e8c\u4e2a\u4e0d\u4f20\u5165<\/p>\n

import React,{useState,useEffect} from ‘react’
\nfunction App(){
\nconst [count,setCount]=useState(1)
\nconst [count1,setCount1]=useState(1)
\nuseEffect(()=>{
\nconsole.log(‘\u6211\u66f4\u65b0\u4e86’);<\/p>\n

document.title=count
\n},[count])
\nreturn(
\n<>
\n<p>{count}<\/p>
\n<p>{count1}<\/p>
\n<button onClick={()=>setCount(count+1)}>\u76d1\u542c\u4f9d\u8d56\u70b9\u51fb<\/button>
\n<button onClick={()=>setCount1(count1+1)}>\u666e\u901a\u70b9\u51fb<\/button>
\n<\/>
\n)
\n}
\nexport default App
\n\u5f53\u6211\u4eec\u70b9\u51fb\u7b2c\u4e00\u4e2a\u6309\u94ae\u65f6\uff0c\u53ef\u4ee5\u770b\u5230\u8c03\u7528\u4e86useEffect()<\/p>\n

 <\/p>\n

\u5f53\u6211\u4eec\u70b9\u51fb\u7b2c\u4e8c\u4e2a\u6309\u94ae\u65f6\uff0c\u867d\u7136\u503c\u66f4\u65b0\u4e86\uff0c\u4f46\u662f\u6ca1\u6709\u8c03\u7528useEffect<\/p>\n

 <\/p>\n

\u6ce8\u610f\u4e8b\u9879\uff1a\u51e1\u662f\u5728useEffect\u4e2d\u7528\u5230\u7684\u6570\u636e\uff0c\u90fd\u5e94\u8be5\u5728\u7b2c\u4e8c\u6b21\u53c2\u6570\u8fdb\u884c\u8bf4\u660e\uff0c\u5426\u5219\u53ef\u80fd\u4f1a\u6709bug<\/p>\n

\u603b\u7ed3\u4e00\u4e0b\uff1a<\/p>\n

1.\u4e0d\u52a0\u4f9d\u8d56\u9879\uff1a\u521d\u59cb\u5316 \uff0c\u66f4\u65b0\u65f6\u90fd\u4f1a\u91cd\u65b0\u6e32\u67d3<\/p>\n

2.\u52a0\u3010\u3011\uff0c\u521d\u59cb\u5316\u6267\u884c\u4e00\u6b21 \u53d1\u9001\u7f51\u7edc\u8bf7\u6c42\u7528\u8fd9\u4e2a<\/p>\n

3.\u52a0\u7279\u5b9a\u4f9d\u8d56\u9879\u3010count\uff0cname\u3011-\u9996\u6b21\u6267\u884c+\u6570\u636e\u53d8\u5316\u65f6\u6267\u884c<\/p>\n

\u53d1\u9001\u7f51\u7edc\u8bf7\u6c42
\n\u9519\u8bef\u6f14\u793a
\n\u4e0d\u53ef\u4ee5\u76f4\u63a5\u5728useEffect\u7684\u56de\u8c03\u51fd\u6570\u5916\u5c42\u76f4\u63a5\u5305\u88f9 await \uff0c\u56e0\u4e3a\u5f02\u6b65\u4f1a\u5bfc\u81f4\u6e05\u7406\u51fd\u6570\u65e0\u6cd5\u7acb\u5373\u8fd4\u56de<\/p>\n

useEffect(async ()=>{
\nconst res = await axios.get(‘http:\/\/geek.itheima.net\/v1_0\/channels’)
\nconsole.log(res)
\n},[])
\n\u6b63\u786e\u6f14\u793a \u5728\u5185\u90e8\u5355\u72ec\u5b9a\u4e49\u4e00\u4e2a\u51fd\u6570\uff0c\u7136\u540e\u628a\u8fd9\u4e2a\u51fd\u6570\u5305\u88c5\u6210\u540c\u6b65<\/p>\n

useEffect(()=>{
\nasync function fetchData(){
\nconst res = await axios.get(‘http:\/\/geek.itheima.net\/v1_0\/channels’) console.log(res)
\n}
\n},[])
\n3.\u6e05\u7406\u526f\u4f5c\u7528
\n\u6dfb\u52a0\u6e05\u7406\u526f\u4f5c\u7528\u51fd\u6570\u540e\uff1a\u4e00\u65e6\u7ec4\u4ef6\u88ab\u9500\u6bc1\uff0c\u5b9a\u65f6\u5668\u4e5f\u88ab\u6e05\u7406<\/p>\n

import { useEffect, useState } from ‘react’<\/p>\n

function Foo() {
\nuseEffect(() => {
\nconst timerId = setInterval(() => {
\nconsole.log(‘\u526f\u4f5c\u7528\u51fd\u6570\u6267\u884c\u4e86’)
\n}, 1000)
\n\/\/ \u6dfb\u52a0\u6e05\u7406\u526f\u79df\u7528\u51fd\u6570
\nreturn () => {
\nclearInterval(timerId)
\n}
\n})
\nreturn <div>Foo<\/div>
\n}
\nfunction App() {
\nconst [flag, setFlag] = useState(true)
\nreturn (
\n<>
\n<button onClick={() => setFlag(false)}>click<\/button>
\n{flag ? <Foo\/> : null}
\n<\/>
\n)
\n}
\nexport default App
\n4\uff0c\u6df1\u5165\u4e86\u89e3
\nuserEffect\u505a\u4e86\u4ec0\u4e48\uff1f
\n\u4f60\u53ef\u4ee5\u544a\u8bc9 React \u7ec4\u4ef6\u9700\u8981\u5728\u6e32\u67d3\u540e\u6267\u884c\u67d0\u4e9b\u64cd\u4f5c\u3002React \u4f1a\u4fdd\u5b58\u4f60\u4f20\u9012\u7684\u51fd\u6570\uff08\u6211\u4eec\u5c06\u5b83\u79f0\u4e4b\u4e3a \u201ceffect\u201d\uff09\uff0c\u5e76\u4e14\u5728\u6267\u884c DOM \u66f4\u65b0\u4e4b\u540e\u8c03\u7528\u5b83\u3002<\/p>\n

userEffect\u90fd\u4f1a\u5728\u6bcf\u6b21\u6e32\u67d3\u4e4b\u540e\u6267\u884c\u5417\uff1f
\n\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5b83\u5728\u7b2c\u4e00\u6b21\u6e32\u67d3\u4e4b\u540e\u548c\u6bcf\u6b21\u66f4\u65b0\u4e4b\u540e\u90fd\u4f1a\u6267\u884c\u3002<\/p>\n

\u4e3a\u4ec0\u4e48\u5728\u7ec4\u4ef6\u5185\u90e8\u8c03\u7528 useEffect\uff1f
\n\u5c06 useEffect \u653e\u5728\u7ec4\u4ef6\u5185\u90e8\u8ba9\u6211\u4eec\u53ef\u4ee5\u5728 effect \u4e2d\u76f4\u63a5\u8bbf\u95ee count state \u53d8\u91cf\uff08\u6216\u5176\u4ed6 props\uff09\u3002\u6211\u4eec\u4e0d\u9700\u8981\u7279\u6b8a\u7684 API \u6765\u8bfb\u53d6\u5b83 \u2014\u2014 \u5b83\u5df2\u7ecf\u4fdd\u5b58\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u3002Hook \u4f7f\u7528\u4e86 JavaScript \u7684\u95ed\u5305\u673a\u5236\uff0c\u800c\u4e0d\u7528\u5728 JavaScript \u5df2\u7ecf\u63d0\u4f9b\u4e86\u89e3\u51b3\u65b9\u6848\u7684\u60c5\u51b5\u4e0b\uff0c\u8fd8\u5f15\u5165\u7279\u5b9a\u7684 React API\u3002<\/p>\n

\u4e09.hook\u4f7f\u7528\u89c4\u5219
\n\u4e0d\u8981\u5728\u5faa\u73af\uff0c\u6761\u4ef6\u6216\u5d4c\u5957\u51fd\u6570\u4e2d\u8c03\u7528 Hook\uff0c \u786e\u4fdd\u603b\u662f\u5728\u4f60\u7684 React \u51fd\u6570\u7684\u6700\u9876\u5c42\u4ee5\u53ca\u4efb\u4f55 return \u4e4b\u524d\u8c03\u7528\u4ed6\u4eec\u3002\u9075\u5b88\u8fd9\u6761\u89c4\u5219\uff0c\u4f60\u5c31\u80fd\u786e\u4fdd Hook \u5728\u6bcf\u4e00\u6b21\u6e32\u67d3\u4e2d\u90fd\u6309\u7167\u540c\u6837\u7684\u987a\u5e8f\u88ab\u8c03\u7528\u3002\u8fd9\u8ba9 React \u80fd\u591f\u5728\u591a\u6b21\u7684 useState \u548c useEffect \u8c03\u7528\u4e4b\u95f4\u4fdd\u6301 hook \u72b6\u6001\u7684\u6b63\u786e\u3002<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

cc from   Mr.\u6307\u5c16<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[24],"tags":[121],"class_list":["post-7054","post","type-post","status-publish","format-standard","hentry","category-value_docs","tag-05-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7054","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=7054"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7054\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=7054"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=7054"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=7054"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}