类拓展

一、创建类

class Person{
	constructor(name) {//构造器
	    this.name = name//实例化属性
	}
	age = 18//实例化属性
	static hobby = "打游戏"//静态属性
}
Person.prototype.sex = "男"//原型属性

let p = new Person("小明")
Person.hobby//打游戏

[!cogs]

%accordion% 这种是活了 %accordion%

class Person {//类
    constructor(name, age) {//构造函数
        this.name = name//实例属性
        this.age = age
    }
}
let p = new Person("张三", 18)
console.log(p); //Person {name: "张三", age: 18}

%/accordion%

%accordion% 这种age已经写死了 %accordion%

class Person {//类
    constructor(name) {//构造函数
        this.name = name//实例属性
    }
    age = 18//实例化属性
}
let p = new Person("张三")
console.log(p); //Person {age: 18, name: "张三"}

%/accordion%

%accordion% 语法糖 %accordion%

class Person {//类
    constructor(name) {//构造函数   ——对象上调用
        this.name = name//实例属性  ——对象上调用
    }
    age = 18//实例化属性
    static hobby = "打游戏"//静态属性，——在类上调用
}
Person.prototype.sex = "男"//原型属性   ——对象上调用
let p = new Person("张三")
console.log(p); //Person {age: 18, name: "张三"}
console.log(Person.hobby); //打游戏

%/accordion%

二、类继承

class Person{
	constructor(name) {
	    return this.name = name
	}
	say(){
		return "呵呵"
	}
}

class Student extends Person{
	constructor(name,age){
		super(name)//继承父类的构造函数方法
		this.age = age//student类自己独有的属性
	}
	saying(){
		return super.say()+"哈哈"//调用父类的原型方法
	}
}

let s = new Student("小明",18)
console.log(s.saying())//呵呵哈哈

[!cogs]

%accordion% 1️⃣😀 %accordion%

class Person {
    constructor(name) {
        this.name = name
    }
    age = 18
}
let p = new Person("张三")

class Student extends Person {

}
let s = new Student()
console.log(s); //Student {age:18, name: undefined}

%/accordion%

%accordion% 2️⃣😂 %accordion%

class Person {
    constructor(name) {
        this.name = name
    }
    age = 18
}
let p = new Person("张三")

class Student extends Person {

}
let s = new Student("李四")
console.log(s); //Student {age:18, name: "李四"}

%/accordion%

%accordion% 3️⃣🤣 %accordion%

class Person {
    constructor(name) {
        this.name = name
    }
    age = 18
}
let p = new Person("张三")

class Student extends Person {
    constructor(name) {
        super(name) //可以更改属性
    }
}
let s = new Student("李四")
console.log(s); //Student {age:18, name: "李四"}

%/accordion%