getBoundingClientRect().width使用react挂钩返回0 getBoundingClientRect().width是一个用于获取元素宽度的方法,它返回一个DOMRect对象,其中包含了元素的位置和尺寸信息。在React中使用挂钩(hooks)时,如果getBoundingClientRect().width返回0,可能是因为在组件渲染时,元素还没有被正确地渲染到DOM中。 要解决这个...
发现React官网已经把componentWillReceiveProps重名为UNSAFE_componentWillReceiveProps，但是我发现了getDerived...
<!-- 引入babel,用于将jsx转为js --> class NewsList extends React.Component{ state = {newsArr:[]} componentDidMount(){ setInterval(() => { //获取原状态 const {newsArr} = this.state //模拟一条新闻 const news = '新闻'+ (newsArr.length+1) //更新状态 this.setState({newsArr:...
react中getDerivedStateFromProps和componentDidUpdate配合使用 React 父组件通过props控制子组件执行不同的方法进行渲染 importReact, {Component}from'react'; classItemextendsComponent{ constructor(props) { super(props) this.state={ content:'', fun1:0, fun2:0, runFun:'fun1', shouldUpdateByFun1:false,...
如果使用import {message} from "antd"中的message则没有问题,但会产生警告 Warning: [antd: message] Static function can not consume context like dynamic theme. Please use 'App' component instead.。📷 复现步骤 | Recurrence stepsModalForm中引用const {message} = App.useApp() ,在ProFormCaptcha组件...
Seeing this on react 16.8.6. componentDidMount() { this.setState({width: this.ref.current.parentElement.clientWidth}) // should be 360, reported as 180 } However, if I introduce a setTimeout(), it works correctly: componentDidMount() { setTimeout(() => { this.setState({width: th...
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importReact, {Component}from'react';classItemextendsComponent{constructor(props) {super(props)this.state= {content:'',fun1:0,fun2:0,runFun:'fun1',shouldUpdateByFun1:false,shouldUpdateByFun2:false,myArgument: [] } }staticgetDerivedStateFromProps(nextProps, prevState) {if(nextProps.fun1!==...
To prevent extra rendering, we can use 'shouldComponentUpdate' in the past, new API 'React.memo' is a high order component which is doing the same things with cleaner API: constGreeting = React.memo(({ text }) =>{ console.log("I'm in Greeting");returnHello, {text}!; }); If th...