对象的扩展

1.对象的简洁表示
2.属性表达式
3.扩展运算符
4.super关键字
5.Object新增方法

 

1.对象的简洁表示
es5
var name = "name";
var age = 18;
var person_es5 = {
    name:name,
    age:age,
    //定义方法
    intro:function(){
        console.log("my name is:"+name,"I am:"+age+"years old")
    }
};
console.log(person_es5)
person_es5.intro();

es6
const person_es6 = {
    name,
    age,
    //定义方法简写
    intro(){
        console.log("my name is:"+name,"I am:"+age+"years old")
    }
}
console.log(person_es6);


2.属性表达式
es5
var filedName = "sex";
var obj = {
    //属性名是直接变成字符串，不会当作引用去查找值
    filedName:18
}
console.log(obj);//filedName:18

es6
const obj_es6 = {
    [filedName]:18
}
console.log(obj);//sex:18


3.扩展运算符...
let {a,b,d} = {a:'hello',b:'world',c:'mickey',d:'tom',e:'minnie'};
console.log(a,b,d)//hello world tom

let {a,b,...d} = {a:'hello',b:'world',c:'mickey',d:'tom',e:'minnie'};
console.log(a,b,d)//hello world {c:'mickey',d:'tom',e:'minnie'}


4.super关键字:指向当前对象的prototype对象
const pro = {
    name:'tom'
};
const obj = {
    name:'mickey',
    getName(){
        console.log(this.name); //mickey
        console.log(super.name);//tom
    }
};
//将pro设置为obj的原型对象;即设置obj的原型为pro
Object.setPrototypeOf(obj,pro)
obj.getName();//tom


5.Object新增方法
a.Object(obj1,obj2):相当于===
b.Object.assign(obj1,obj2):浅拷贝
c.Object.setPrototypeOf(obj1,obj2) Object.getPrototypeOf(obj)
d.Object.entries(obj) Object.keys(obj) Object.values(obj)

let res = Object.is("tom","tom");
console.log(res)                //true
console.log("tom"==="tom");     //true

let obj = {},obj2 = obj;
console.log(Object.is(obj,obj2)) //true


let obj1 = {name:"tom"};
let obj2 = {age:19};
Object.assign(obj1,obj2);
console.log(obj1,obj2) //obj1:{name:"tom",age:19} obj2:{age:19}


let obj = {
    name:"tom",
    age:18,
    sex:"man"
}
for(let key of Object.key(obj)){
    console.log(key);
}
for(let value of Object.values(obj)){
    console.log(value);
}
for(let [key,value] of Object.entries(obj)){
    console.log(key,value);
}