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  • 总结各种奇葩原型继承,面试向

    1. 原型链继承

    function Brother(name){

      this.name = name;

      this.wives = ["奶茶"];

      this.marry = function(){};

    }

    function Employee(name) {

      this.name = name;

    }

    Employee.prototype = new Brother();

    优点:书写简单

    缺点: 无法给父类构造函数传参,子类会继承父类的所有引用类型,一旦原地修改就会影响所有子类。

    const brother = new Brother("刘强东");

    const employee1 = new Employee("刘强东的兄弟");

    const employee2 = new Employee("刘强东的兄弟2");

    console.log(employee1.wives); // 奶茶

    console.log(employee2.wives); // 奶茶

    employee1.wives.push("绿茶");

    console.log(employee1.wives); // 奶茶,绿茶

    console.log(employee2.wives); // 奶茶,绿茶

    employee1.wives = ["绿茶"]; // 指向不同对象

    console.log(employee1.wives); // 绿茶

    console.log(employee2.wives); // 奶茶,绿茶

    2.借用构造函数

    function Brother(name){

      this.name = name;

      this.wives = ["奶茶"];

          this.marry = function(){};

    }

    function Employee(name, age) {

      Brother.call(this, name);

      this.age = age;

    }

    缺点:父类方法内的函数每次都会生成新的拷贝;通过prototype定义的方法无法继承

    3. 组合继承 (原型链 + 借用构造函数)

    function Brother(name){

      this.name = name;

      this.wives = ["奶茶"];

    }

    Brother.prototype.marry = function() {}

    function Employee(name, age) {

      Brother.call(this, name);

      this.age = age;

    }

    Employee.prototype = new Brother();

    缺点: 多次调用构造函数

    4.原型式继承  duck type 鸭式辨型

    function object(o) {

      function F(){}

      F.prototype = o;

      return new F();

    }

    或者直接object.create(o);

    使用场合:没必要构建构造函数,仅仅是想模拟一个对象的时候

    缺点:同原型链

    5.寄生继承

    function(original){

      newObj = Object(original)

      newObj.newFunc =(){}

      return newObj

    }

    缺点:方法在函数中定义,无法得到复用

    6.寄生组合

    function inheritPrototype(subType, supType) {

      var p = Object(supType.prototype);

      p.constructor = subType;

      subType.prototype = p;

    }

    function subType(){

      supType.call(this);

    }

    inheritProptype(subType, supType)

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  • 原文地址:https://www.cnblogs.com/huashiyiqike/p/10545189.html
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