效果图：App.jsximportReact,{Component}from'react'importstylefrom'./index.module.less'exportdefaultclassAppextendsComponent{state={width:0,left:0}enter=(event)=>{const{clientWidth,offsetLeft}=event.targetthis.setState({width:clientWidth,left:offsetLeft})}leave=()=>{this.setState(()=>({width:0}))}render(){const{width,left}=this.statereturn(<>
