类和 Json对象

//类
    class Person {
        constructor(name,age,sex) {
            this.name = name;
            this.age = age;
            this.sex = sex;
        }
        getName(){
            return this.name;
        }
        getAge(){
            return this.age;
        }
    }
    let p1 =new Person('zhang',20,'nan');
    console.log(p1.getAge());
    //继承父类
    class Student extends Person{
        //构造函数
        constructor(name,age,sex,school) {
            super(name,age,sex);//继承父类的属性
            this.school=school;
        }
    }
    let s1 =new Student('zhang1',20,'nan','文化小学');
    console.log(s1.school);//文化小学
    //Json对象
    console.log(typeof s1);//object
    //对象转JSON字符串
    let s1String =JSON.stringify(s1);
    console.log(typeof s1String );//string
    //JSON字符串转对象
    let s1Obj = JSON.parse(s1String);
    console.log(typeof s1Obj)//object
        //包含js
    // node 中 js 包含 用 var {解构} = require("./a")
    // 前端JavaScript 中 用 import {解构} from "./a.js"
    //a.js 中 需要暴露出内容 用export暴露
    //暴露出类
    export class Person{
    }
    //暴露出变量
    export let a=55;
    //暴露默认方法
    export default function(){
        //node接收 当前js 时
         let fun = require('./a');
         //fun();
        //JavaScript 接收时
         // import hh from "./a.js";
         //  hh() 直接调用
    }