Object对象

一、定义对象

var obj={}

var obj = new Object()

二、对象属性赋值

三、获取对象属性

1、Object.keys()

2、Object.getOwnPropertyNames()

四、对象属性模型的相关方法

1、Object.getOwnPropertyDescriptor()

2、Object.defineProperty()

Object.defineProperty(obj, prop, descriptor)

3、Object.defineProperties()

Object.defineProperties(obj, props)

4、Object.propertyIsEnumerable()

五、控制对象状态的方法

1、Object.preventExtensions()

2、Object.isExtensible()

3、Object.seal()

4、Object.isSealed()

5、Object.freeze()

6、Object.isFrozen()

六、原型链的相关方法

1、Object.create()

2、Object.getPrototypeOf()

七、Object方法扩展

1、Object.is()

 console.log(Object.is(120, 120)); //true
 console.log(Object.is(NaN, NaN)); //true
 console.log(NaN === NaN); //false

2、Object.assign()

const config1 = {
            host: 'localhost',
            port: 3306,
            name: 'root',
            password: '123'
        };
        const config2 = {
            host: 'http://www.4399.com',
            port: '33060',
            name: 'root2',
            password: '456'
        };
        //{host: 'http://www.4399.com', port: '33060', name: 'root2', password: '456'}
        console.log(Object.assign(config1, config2)); //后面参数把前面覆盖

3、Object.setPrototypeOf()和Object.getPrototypeOf()

const school = {
            name: 'GDUF'
        };
        const cities = {
            xiaoqu: ['广州', '肇庆', '清远']
        };
        Object.setPrototypeOf(school, cities); //设置school原型

console.log(Object.getPrototypeOf(school)); //获取school原型

4、Object.keys()

Object.keys(obj);

5、Object.values()

Object.values(obj);

6、Object.entries()

Object.entries(obj);

7、Object.fromEntries()

Object.fromEntries(obj);