JavaScript传播运算符不会将值复制到另一个对象

Question

点差算子到底如何工作？

这是我的代码...

switchNameHandler = (newName) =>{

        let newPeople = [...this.state.People];

        newPeople[0].name = newName;

        this.setState({
          People:[...newPeople]
        })

        newPeople[0].name="John"
}

我希望更改this.state.People后不会更改p[0].name。为什么会改变？