取數(shù)據(jù)后如何用數(shù)據(jù)初始化state？

import React from 'react';
class Demo extends React.Component{
  constructor(props){
    super(props)
    this.state{
      initData: ''
    }
  }

  render(){
      return(
        <div>{ this.state.initData }<div>
      )
  }
}
function mapStateToProps(state) {
  const { demoData } = state.demo;
  return { demoData };
}
export default connect(mapStateToProps)(Demo );

請(qǐng)問(wèn)如何使用demoData初始化state呢？用了幾個(gè)鉤子函數(shù)都沒(méi)成功。