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 每一个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>个人名字是{this.state.success?this.state.data[0].user:''}</h2>
                {this.props.isAuth?<Redirect to='/dashboard'></Redirect>:null}
                <h2>你没有权限须要登陆</h2>
                <button onClick={this.props.login}>登陆</button>
            </div>
        )
    }
}

export default Auth