When learning, the teacher encounters and uses itObject中的方法,So list it,See what it can do,It is also convenient for future development and direct use

1 Object.assign

Copies all enumerable returned and own properties from one or more source objects to target objects

const target={
    a:1,b:2}
const source={
    b:4,c:5}

const target=Object.assign(target,source)

第一个参数为目标对象,后面的参数Can be an object that requires one or more replications,The final structure returnsThe target object after copying

注意1：使用Object.assignMaking a deep copy only copies the first level of references,Therefore, deep copying of multi-level reference objects is not possible

注意2：复制null和undefined时会忽略,Only enumerable types and their own properties can be copied,一般只有stringHas its own enumerable properties

2 Object.create

用于创建一个新对象,Use an existing object as a prototype for a new object

使用Object.create实现继承

function Person(name,age){
    
	this.name=name
	this.age=age
}

Person.prototype.getName=function(){
    
	return this.name
}
function Student(name,age,grade){
    
	Person.call(this,name,age)
	this.grade=grade
}

Student.prototype=Object.create(Person.prototype)

Strdent.prototype.constructor=Student

3 Object.defineProperty

直接在一个对象上定义新的属性或修改现有属性,并返回该对象

Object.defindPropertiy(obj,{
    
	set(val){
    
		obj==val	
	}
	get(){
    
		return obj	
	}
})

4 Object.entries

返回一个键值对数组

5 Object.getOwnPropertyNames

Returns the property names of all properties of an object（包括不可枚举、属性,但不包括symbol值作为名称的属性）

6 Object.getOwnPropertySymbols

Returns an object to useSymbol值作为属性名

7 Object.hasOwn

Determines whether the property is a direct property of the object,This method does not check properties on the object's prototype chain

8 Object.keys

Returns an array of object enumerable property names

9 Object.values

返回对象的属性值数组