ES5形式

  function fun() {
    this.name = 'fun',
    this.arr = [1,2,3]
  }

  fun.prototype.myLog = function() {
    console.log(this.arr);
  }

  function cFun () {
    fun.call(this) //call調(diào)用父函數(shù) 繼承父函數(shù)的屬性
    this.type = 'child'
  }

  cFun.prototype = fun.prototype // 構(gòu)造函數(shù)的原型對(duì)象指向要繼承的父函數(shù)的原型對(duì)象
  cFun.prototype.constructor = cFun

  var c1 = new cFun()
  console.log(c1);
  c1.myLog()
  console.log(c1 instanceof cFun); // true
  console.log(f1 instanceof cFun); // true

執(zhí)行結(jié)果如圖：

image.png

缺點(diǎn)：因?yàn)楦负瘮?shù)和子函數(shù)都是同一個(gè)對(duì)象，導(dǎo)致父函數(shù)和子函數(shù)的實(shí)例對(duì)象，在執(zhí)行instanceof時(shí)，都為true 無(wú)法區(qū)分。
用Object.creacte(fun.prototype)創(chuàng)建中間對(duì)象的形式可以解決這個(gè)問(wèn)題

ES6形式

  class Teacher {
    constructor(name) {
        this.name = name
        this.age = 30
    }
    sayHi() {
        console.log(`hello everyone，我叫${this.name}`);
    }
  }

  class Student extends Teacher {
    constructor(name) {
        super(name)
        this.name = name
    }
    sayHello() {
        console.log(`大家好，我叫${this.name}`);
    }
  }

  const stu1 = new Student('張三')
  console.log(stu1);
  stu1.sayHello()
  stu1.sayHi()

結(jié)果如下：

image.png