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外观

ES-14 种对象操作方法 ​

1.获取原型 ​

javascript
const obj = { a: 1, b: 2 };
const proto = Object.getPrototypeOf(obj);
console.log(proto);
console.log(obj.__proto__);
console.log(Object.prototype);
const obj = { a: 1, b: 2 };
const proto = Object.getPrototypeOf(obj);
console.log(proto);
console.log(obj.__proto__);
console.log(Object.prototype);

2.设置原型 ​

javascript
const obj = { a: 1, b: 2 };
Object.setPrototypeOf(obj, { c: 3, d: 4 });
console.log(obj.__proto__);
const obj = { a: 1, b: 2 };
Object.setPrototypeOf(obj, { c: 3, d: 4 });
console.log(obj.__proto__);

3.获取对象的可扩展性 ​

javascript
const obj = { a: 1, b: 2 };
const isexensible = Object.isExtensible(obj);
console.log(" isexensible: ", isexensible);
const obj = { a: 1, b: 2 };
const isexensible = Object.isExtensible(obj);
console.log(" isexensible: ", isexensible);

4.获取自有属性 ​

javascript
const obj = { a: 1, b: 2 };
Object.getOwnPropertyNames(obj);
console.log(
  "Object.getOwnPropertyNames(obj): ",
  Object.getOwnPropertyNames(obj)
);
const obj = { a: 1, b: 2 };
Object.getOwnPropertyNames(obj);
console.log(
  "Object.getOwnPropertyNames(obj): ",
  Object.getOwnPropertyNames(obj)
);

5.禁止扩展对象 ​

javascript
const obj = { a: 1, b: 2 };
Object.preventExtensions(obj);
obj.c = 3;
console.log(obj); // {a:1.b:2}
const obj = { a: 1, b: 2 };
Object.preventExtensions(obj);
obj.c = 3;
console.log(obj); // {a:1.b:2}

6.拦截对象操作 ​

javascript
Object.defineProperty();
Object.defineProperty();

7.判断是否为自身属性 ​

javascript
const obj = { a: 1 };
console.log(obj.hasOwnProperty("a")); // true
const obj = { a: 1 };
console.log(obj.hasOwnProperty("a")); // true

8.[[GET]] ​

javascript
const obj = { a: 1 };
console.log(a in obj);
console.log(obj.a);
const obj = { a: 1 };
console.log(a in obj);
console.log(obj.a);

9.[[SET]] ​

javascript
const obj = { a: 3 };
obj.a = 4;
const obj = { a: 3 };
obj.a = 4;

10.delete ​

javascript
const obj = { a: 1 };
delete obj.a;
const obj = { a: 1 };
delete obj.a;

11.Enumerate ​

javascript
const obj = { a: 1, b: 2 };
for (key in obj) {
  console.log(obj[key]);
}
const obj = { a: 1, b: 2 };
for (key in obj) {
  console.log(obj[key]);
}

12.获取键集合 ​

javascript
const obj = { a: 1, b: 2 };
let a = Object.keys(obj); // ['a','c']
console.log(obj);
console.log(a[0]);
const obj = { a: 1, b: 2 };
let a = Object.keys(obj); // ['a','c']
console.log(obj);
console.log(a[0]);

13.函数调用 ​

javascript
const obj = { a: "i am is a obj" };
var a = "globalContext";
function fn() {
  console.log(this.a);
}
fn(); // globalContext

obj.fn = fn;
obj.fn(); // i am is a obj
const obj = { a: "i am is a obj" };
var a = "globalContext";
function fn() {
  console.log(this.a);
}
fn(); // globalContext

obj.fn = fn;
obj.fn(); // i am is a obj

14.new ​

javascript
function Person() {}
const person1 = new Person();
function Person() {}
const person1 = new Person();