悟透javascript代码摘记

function Class(){
	var aDefine = arguments[arguments.length-1];//最后一个参数为类定义
	if (!aDefine)//没有参数就返回
	{
		return;
	}
	var aBase = arguments.length > 1?arguments[0]:object;//解析基类
	function prototype_(){};//构造prototype的临时函数，用于挂接原型链
	prototype_.prototype = aBase.prototype;//准备传递prototype
	var aPrototype = new prototype_();//建立类要用的prototype

	for (var member in aDefine)//复制类定义到当前类的prototype
	{
		if (member != "Create")//构造函数不用复制
		{
			aPrototype[member] = aDefine[member];
		}
	}
	//如果有构造函数
	if (aDefine.Create)
	{
		var aType = aDefine.Create;//类型即为该构造函数
	}
	else{//否则为默认构造函数。
		aType = function(){
			this.base.apply(this,arguments);
		}
	}

	aType.prototype = aPrototype;		//设置类（构造函数）的prototype
	aType.Base = aBase;					//设置类型关系
	aType.prototype.Type = aType;		//为本类对象扩展一个Type属性
	return aType;						//返回构造函数作为类
}

//根类object定义
function object(){};//定义小写的object根类，用于实现最基础的方法等
object.prototype.isA = function(aType){//判断是否属于某类型
	var self = this.Type;
	while (self)
	{
		if(self == aType) return true;
		self = self.Base;
	}
	return false;
}
//调用基类构造函数
object.prototype.base = function(){
	var Caller = object.prototype.base.caller;
	Caller && Caller.Base && Caller.Base.apply(this,arguments);
}

//应用效果
//默认派生自object基本类
var Person = Class({
	Create:function(name,age){
		this.base();
		this.name = name;
		this.age = age;
	},
	sayHello:function(){
		alert("Hi,I am " + this.name + ", "  + this.age + " years old.");
	}
});
//Employee派生自Person
var Employee = Class(Person,{
	Create:function(name,age,salary){
		this.base(name,age);//调用基类的构造函数
		this.salary = salary;
	},
	showMeTheMoney:function(){
		alert(this.name + "'s salary is: $" + this.salary);
	}
});

var wml = new Person("Wu Mingli",29);
//wml.sayHello();
//var xyd = new Employee("Xu yedong",28,7500);
//xyd.showMeTheMoney();
var lyp = new wml.Type("Lv yaping",25);
lyp.sayHello();