5.对象解析赋值

1、对象解构是为了简化对象属性取值

解构没有顺序，但要和对象属性名称保持一致，如下：

    <script>
        const user = {
            username:'张三',
            age:28,
            getUsername(){
                return this.username;
            }
        }
        console.log(user.username);
        console.log(user.age);
        console.log(user.getUsername());
        let {username,age} = user;
        console.log(age);
</script>

２、解构也可以定义到对象的函数方法中

    <script>
        let { abs,random } = Math;
        console.log(abs(-1));
        console.log(random());
    </script>