条件渲染和列表渲染

import React,{FC} from "react"
type IProps ={
    flag:boolean
}
const Show:FC<IProps>=(props)=>{
{
  if(props.flag){
   return <div>已经登陆</div>
  }  
    else{
        return <div>未登录</div>
    }
    }
}
export default Show

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import * as serviceWorker from './serviceWorker';
import Show from "@/components/show"
let user={
  name:"张三",
  age:18
}
ReactDOM.render(
<Show flag={true}></Show>,
  document.getElementById('root')
);
serviceWorker.unregister();

可以使用&&进行条件渲染

const Show:FC<IProps>=(props)=>{
{
    return <div>
        {props.flag&&<div>已经登录</div>}
    </div>
    }
}