JavaScript面向对象编程

[suoyuesmile]

参考1：Javascript面向对象编程（一）：封装
参考2：Javascript面向对象编程（二）：构造函数的继承
参考3：Javascript面向对象编程（三）：非构造函数的继承

[suoyuesmile]

实例化对象的3种方法

// 1.生成实例对象的原始模式
var Cat = {
	name : '',
	color ： ''
}
var cat1 = {};
cat1.name = "大毛";
cat1.color = "黄色";
var cat2 = {};
cat2.name = "二毛";
cat2.colot = "黑色";

// 改进
function Cat(name, color) {
	return {
		name:name,
		color:color
	}
}
var cat1 = Cat("大毛","黄色");
var cat2 = Cat("二毛","黑色");

// 2.构造函数
function Cat(name, color) {
	this.name = name;
	this.color = color;
}
var cat1 = new Cat("大毛","黄色");
var cat2 = new Cat("二毛","黄色");
alert(cat1.name);
alert(cat1.color);

// 3.Prototype模式
function Cat(name, color) {
	this.name = name;
	this.color = color;
}
Cat.prototype.type = "猫科动物";
Cat.prototype.eat = function(){
	alert("吃老鼠");
};
var cat1 = new Cat("大毛","黄色");
var cat2 = new Cat("二毛","黑色");
alert(cat1.type);
cat1.eat();

alert(Cat.prototype.isPrototypeOf(cat1));
alert(Cat.prototype.isPrototypeOf(cat2));

alert(cat1.hasOwnProperty("name"));
alert(cat1.hasOwnProperty("type"));

alert("name" in cat1);
alert("type" in cat1);

for(var prop in cat1) {
	alert("cat1[" + prop + "]=" + cat1[prop]);
} 
```

[suoyuesmile]

构造函数实现继承的5种方法

function Animal(){
	this.species = "动物";
}

function Cat(name, color){
	this.name = name;
	this.color = color;
}

//1. 构造函数绑定
function Cat(name, color) {
        Animal.apply(this, arguments);
 	this.name = name;
 	this.color = color;
 }
ar cat1 = new Cat("大毛","黄色");
alert(cat1.species); 

//2. prototype模式
Cat.prototype = new Animal();
//删除Cat的prototype对象，赋予一个新值
Cat.prototype.constructor = Cat;
//手动纠正继承链
vat cat1 = new Cat("大毛","黄色");
alert(cat1.species);

//3. 直接继承prototype 
function Animal(){ }
Animal.prorotype.species = "动物";
Cat.prototype = Animal.prototype;
Cat.prototype.constructor = Cat;
var cat1 = new Cat("大毛","黄色");
alert(cat1.species);
//实际把Animal的原型构造也改变了
alert(Animal.prototype.constructor);

//4. 利用空对象为中介
 var F = function(){};
 F.prototype = Animal.prototype;
Cat.prototype = new F();
cat.prototype.constructor = Cat;
 alert(Animal.prototype.constructor);
//封装成函数
function extend(Child, Parent) {
	var F = function(){};
	F.prototype = Parent.prototype;
	Child.prototype = new F();
	Child.prototype.constructor = Child;
	Child.uber = Parent.prototype;
	//实现继承的完备性
}
extend(Cat, Animal);
var cat1 = new Cat("大毛","黄色");
alert(cat1.species);

//5. 拷贝继承
function Animal(){}
Animal.prototype.speices = "动物";
function extend2(Child,Parent){
	var p = Parent.prototype;
	var c = Child.prototype;
	for (var i in p) {
		c[i] = p[i];
	}
	c.uber = p;
}
//将父亲对象的原先属性全部拷贝给子

[suoyuesmile]

非构造函数实现继承的3种方法

var Chinese = {
	nation: "**"
};
var Doctor = {
	career: "医生";
};

//1. Object方法
function object(o) {
	function F() {}
	F.prototype = o;
	return new F();
}
var Doctor = object(Chinese);

//2. 浅拷贝
function extendCopy(p) {
	var c = {}
	for (var i in p){
		c[i] = p[i];
	}
	c.uber = p;
	return c;
}
var Doctor = extendCopy(Chinese);

//3.深拷贝
function deepCopy(p, c){
	var c = c || {};
	for (var i in p){
		if(typeof p[i] === 'object'){
			c[i] = (p[i].constructot === Array) ? [] : {};
			deepCopy(p[i], c[i]);
		}else {
			c[i] = p[i];
		}
		return c;
	}
}