浅谈JavaScript 继承机制的实现(4)

Chinese.prototype.constructor = Chinese; //constructor属性时指向它的构造函数  
var chin1 = new Chinese("小明"); 
chin1 instanceof Chinese; //true  
chin1 instanceof Human; //true 
function Human(){   //定义Human类
 this.species = "Human";
}
function Chinese(name){
 this.name = name;
}
Chinese.prototype = new Human(); //原型对象指向Human类
Chinese.prototype.constructor = Chinese; //constructor属性时指向它的构造函数
var chin1 = new Chinese("小明");
chin1 instanceof Chinese; //true
chin1 instanceof Human; //true
这样就实现了真正意义上的继承.

相比对象冒充的方法,这样的写法不够直观.

但同时也解决了重复生成函数的问题.

 

最后,把原型继承实现简单的封装:

[javascript]
Object.prototype.extendTo = function(parent) { 
    this.prototype = new parent(); 
    this.prototype.constructor = this; 
    this.uber = parent.prototype; 
} 
 
function Human(){       //定义Human类  
    this.species = "Human"; 
    this.fun = function() { 
        return 0; 
    }; 
} 
 
function Chinese(name){ 
    this.name = name; 
} 
 
Chinese.extendTo(Human); //实现继承.  
 
var chin1 = new Chinese("小明"); 
Object.prototype.extendTo = function(parent) {
 this.prototype = new parent();
 this.prototype.constructor = this;
 this.uber = parent.prototype;
}

function Human(){   //定义Human类
 this.species = "Human";
 this.fun = function() {
  return 0;
 };
}

function Chinese(name){
 this.name = name;
}

Chinese.extendTo(Human); //实现继承.

var chin1 = new Chinese("小明");

 摘自 简生的代码备忘录