对象解构

1、常规对象

常规语法：

let {username,age} ={ username:"sunday",age:18 }
    console.log(username);//sunday
    console.log(age);//18

重命名语法：

    let {username:uname,age} ={ username:"sunday",age:18 }
    console.log(uname);//sunday
    console.log(age);//18

2、对象数组

    let users=[{ username:"sunday",age:18 },{ username:"rt",age:19 }]
    let [{username,age},{username:uname,age:age2}] =users
    console.log(username);//sunday
    console.log(age);//18
    console.log(uname);//rt
    console.log(age2);//19

3、多级对象（对象嵌套对象）

        let users = [{
            username: "sunday",
            friends: {
                username:"rt",
                age:17
            }
        }]
        let [{username,friends:{username:uname,age}}]=users;
        console.log(username);//sunday
        console.log(uname);//rt

4、函数传参

        let users = [{
            username: "sunday",
            friends: {username:"rt",age:17}
        }]
        function reader([{friends}]){
            console.log(friends);//{username:"rt",age:17}
        }
        reader(users);