Javascript OOP.md

封装

function ->
constructor -> prototype

// 将不变的属性和方法定义在 prototype 上  
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("hello", "yellow");

验证方法:

1. isPrototype
2. hasOwnProperty
3. in

继承

1. 构造函数绑定

Parent.apply(this, arguments);

2. prototype 模式

Cat.prototype = new Animal();
// 必须手动纠正继承链
Cat.prototype.constructor = Cat;
var cat1 = new Cat("大毛","黄色");
alert(cat1.species); // 动物

3. 直接继承 prototype

// 任何对 Cat.prototype 的修改，都会反映到 Animal.prototype
Cat.prototype = Animal.prototype;
Cat.prototype.constructor = Cat;
var cat1 = new Cat("大毛","黄色");
alert(cat1.species); // 动物

4. {} 为中介

function extend(Child, Parent) {

    var F = function () {};
    F.prototype = Parent.prototype;
    Child.prototype = new F();
    Child.prototype.constructor = Child;
    Child.uber = Parent.prototype;
}

5. 拷贝继承  

function extend2(Child, Parent) { var p = Parent.prototype; var c = Child.prototype; for (var i in p) { 　　c[i] = p[i]; 　　} c.uber = p; }

## 非构造函数的继承  
**更像是组合**  
深拷贝:  

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