react之异步请求数据，render先行渲染报错，未拿到数据

import React from 'react'
import {connect} from 'react-redux'
import { Redirect} from 'react-router-dom'
import axios from 'axios'
import {login} from './Auth.redux.js'
//两个reducers 每个reducers都有一个state
@connect(
(state)=>state.auth,
{login}
)
class Auth extends React.Component{
constructor(props){
super(props)
this.state={
data:{},
success:false
//解决方法设置一个开关，当数据请求成功，置为true
}
}
componentDidMount(){
axios.get('/data')
.then(res=>{
if(res.status===200){
this.setState({data:res.data,success:true})
console.log(this.state.data[0].user)
debugger
}
})
}
render(){
return (
<div>
<h2>我的名字是{this.state.success?this.state.data[0].user:''}</h2>
{this.props.isAuth?<Redirect to='/dashboard'></Redirect>:null}
<h2>你没有权限需要登录</h2>
<button onClick={this.props.login}>登录</button>
</div>
)
}
}
export default Auth