老师你好，您在课堂中提到，pureComponent 浅比较只比较对象的第一层数据，但为什么我定义了层次很深的对象，pureComponent也能对比出来呢？changeObjName 函数运行后生效了

class ArrList extends React.PureComponent {
    constructor() {
        super()
        this.state = {
            obj: { age: {value: {num: {a: {b:{c:{d:{e:{name: '孙悟空'}}}}}}}} },
        }
    }
    changeObjName = ()=>{
        var copy = JSON.parse(JSON.stringify(this.state.obj));
        copy.age.value.num.a.b.c.d.e.name = '猪八戒';
        this.setState({
            obj: copy
        })
    }
    render() {
        return <div>
            <ul>
                <li>
                    {this.state.obj.age.value.num.a.b.c.d.e.name }
                </li>
            </ul>
            <button onClick={this.changeObjName }>change name</button>
        </div>
    }
}