js继承模式

Posted 2021-03-14 巷陌i

 1、传统形式 ----> 原型链
     过多的继承了没用的属性

Grand.prototype.lastName = "1";
function Grand(){
}
var grand = new Grand();
Father.prototype = grand;
function Father() {
}
var father = new Father();
Son.prototype = father;
function Son() {
}
var son = new Son();

 2、借用构造函数
     不能继承借用构造函数的原型
     每次构造函数都要夺多走一个函数

function Person(name, sex, age) {
     this.name = name;
     this.sex = sex;
     this.age = age;
 }

 function Student(name, sex, age, grand) {
     Person.call(this, name, sex, age);
     this.grand = grand;
 }

 var student = new Student();

 3、共享原型     //缺点 :一个值改另一个也跟这改
     不能随便改动自己的原型

Father.prototype.lastName = ‘Deng‘;

 function Father() {

 }

 function Son() {

 }
 function inherit(Target , Origin){
     Target.prototype = Origin.prototype
 }
 inherit(Son , Father);
var son = new Son();
var father = new Father();

 4、圣杯模式

 function inherit(Target , Origin){
     function F(){}
     F.prototype = Origin.prototype;
     Target.prototype = new F();
     Target.prototype.constructor = Target;
     Target.prototype.uber = Origin.prototype;
 }
 Father.prototype.lastName = ‘Deng‘;
 function Father() {
 }

 function Son() {
 }

 inherit(Son , Father);
 var son = new Son();
 var father = new Father();

私有化变量的应用

 function Li(name , wife){
     var preareWife = "xiaozhang";
     this.name = name;
     this.wife = wife;
     this.divorce = function () {
         this.wife = preareWife;
     };
     this.changPrepareWife = function (target) {
         preareWife = target;
     };
     this.sayPrapreWife = function () {
         console.log(preareWife);
     }
 }
 var li = new Li("li" , "xiaoLi")