React父子组件渲染顺序

import React, { Component } from 'react';
class Children extends Component {
    constructor(props) {
        super(props);
        console.log('son constructor');
    }
    componentDidMount() {
        console.log('son mounted')
    }
    render() {
        console.log('son render')
        return(
            <div>son</div>
        )
    }
}
export { Children };
class Parent extends Component {
    constructor(props){
        super(props);
        console.log('parent constructor')
    }
    componentDidMount() {
        console.log('parent mounted')
    }
    render() {
        console.log('parent render')
        const { children } = this.props;
        return(
            <div>
                <p>parent</p>
                <div>{children}</div>
            </div>
        )
    }
}
export {Parent};

打印结果：

思考：在componentDidMount执行之前先render一次，目的就是先去渲染子组件；
挂载dom节点是一个由内向外的过程。