1.class简单应用

//传统对象 - function
function Course(teacher,course){this.teacher=teacher;this.course=course;
}
Course.prototype.getCourse=function(){return `teacher is ${this.teacher},course:${this.course}`
}const course=new Course('aa','ES6');
course.getCourse()//Es6
class Course{constructor(teacher,course){this.teacher=teacher;this.course=course;}//拓展方法getCourse(){return `teacher is: ${this.teacher},course is ${this.course}`}
}const course =new Course('aa','ES6');
course.getCourse()

2.class的类型

console.log(typeOf course)  //function

3.class的prototype

// 有区分，但本质类型相同function Course(teacher, course) {this.teacher = teacher;this.course = course;}class Course1 {// init 实例会默认执行constructor(teacher, course) {this.teacher = teacher;this.course = course;}// 拓展方法getCourse() {return `teacher is:${this.teacher}, course: ${this.course}`;}}

4.class & 函数对象 属性

console.log(course.hasOwnProperty('teacher')); // true

5.属性定义 构造器 & 顶层定义 两种定义方式

class Course {
// init 实例会默认执行constructor(teacher,course){this.teacher=teacher;this.course=course;}//拓展方法
getCourse(){return `teacher is : ${this.teacher},course is : $ {this.course}`}get teacher(){//留有空间return this.teacher}set teacher(val){//留有空间this.teacher=val}
}//意义何在?
//1. js如何建立只读变量
class Course{//init 实例会默认执行constructor(teacher,course){this._teacher=teacher;this.course=course;}//拓展方法getCourse(){return `teacher is :${this.teacher},course is :${this.course}`}get teacher(){//留有空间return this._teacher}
}//修改只读变量，会报错么 - 无法改变但是不会报错2.如何建立一个私有属性
class Course{constructor(){this._teacher=teacher;//在constrctor作用域内定义一个局部变量let _course = 'es6';//内部通过闭包的形式去暴露该变量this.getCourse=()=>{return this._course;}}
}class Course{#course = 'es6';constructor(teacher,course){this._teacher = teacher;}get course(){return this.#course;}set course(val){if(val){this.#course = val}}
}//3.封装核心 - 适配器模式
// 底层封装中台业务 core
class utils{constructor(core){this._main=core;this._name='my-utils';this._id='123'}//fullName:{firstName:" ",lastName:'',name:''}get name(){return {...this._main.fullName,...{name: `utils is ${this.name}`}}}get id(){return{...this._main.id,id:this._id}}set name(val){//valid safteythis._name=val;}
}

6.静态方法 - 直接挂载在类上的方法无需实例化获取(static)

//es5实现
function Course(){// ...
} 
Course.ring=function(){//...
}//es6实现class Course{constructor(){//...}static ring(){//...}}
Course.ring();//同一个class 多个实例，用于全局对象变量问题

7.继承

function Course(){
//...
}
//不用实例化可以调用 Course.ring()
Course.ring = function(){//...}//实例化后才可以调用Course.prototype.send=function(){//...}function Child(){Course.call(this,'aa','es6')this..run=function(){//...}}Child.prototype=Course.prototype;

//es6class Course {constructor(){//...}static ring(){}send(){}
}// => 工厂模式class Child extends Course{constructor(){super('aa',es6) //相当于Course.call(this,'aa','es6')}run(){}}