js 面向对象程序设计

//ex1 工厂模式

function creatPerson(name,age,job){

var o = new Object();

o.name = name;

o.age = age;

o.job = job;

o.sayName = function(){

console.info(name);

}

return o;

}

var person1 = creatPerson("je",18,"stduent");

var person2 = creatPerson("ji",28,"man");

console.info(person1 instanceof creatPerson);

console.info(person2);

//ex2 构造函数

function Person(name,age,job){

this.name = name;

this.age = age;

this.job = job;

this.sayName = function(){

console.info(name);

}

}

var person1 = new Person("je",18,"stduent");

var person2 = new Person("ji",28,"man");

console.info(person1 instanceof Person); //判断哪个类

console.info(person1.constructor==Person);       //指向类 ，一般用instanceof

console.info(person2);

//ex2.1构造函数优化--没有封装性

function Person(name,age,job){

this.name = name;

this.age = age;

this.job = job;

this.sayName = sayName;

}

function sayName(){

console.info(name);

}

var person1 = new Person("je",18,"stduent");

//ex3 原型模式

function Person(){

}

Person.prototype.name = 'Je';

Person.prototype.age = '29';

Person.prototype.job = 'student';

Person.prototype.sayName = function(){

console.info(this.name);

}

var person1 = new Person();

var person2 = new Person();

console.info(person1.sayName==person2.sayName);  //引用的是同一个方法

console.info(Person.prototype);      //指向原型对象

console.info(Person.prototype.constructor);   //原生的Person 函数

console.info(person1.prototype);              //undefined

console.info(person1.prototype.constructor);  // 'constructor' of undefined

console.info(Person.prototype.isPrototypeOf(person1)); //true 用来确定实例与原型是否有关系

console.info(Object.getPrototypeOf(person1));         //Sc5的新方法 ==Person.prototype ie9支持

//ex3.1 delete、 hasOwnProperty使用

//获取所有实例方法 Object.keys();--可枚举

//Object.getOwnPropertyNames();--不可枚举

function Person(){

}

Person.prototype.name = 'Je';

Person.prototype.age = '29';

Person.prototype.job = 'student';

Person.prototype.sayName = function(){

console.info(this.name);

}

console.info(Object.keys(Person.prototype));  //["name", "age", "job", "sayName"]

var person1 = new Person();

person1.name = 'ne';

console.info(Object.keys(person1));    //["name"]

console.info(Object.getOwnPropertyNames(person1));   //["name"]

console.info(person1.name); //ne

console.info(person1.hasOwnProperty("name")); //true  判断属性是在原型中还是实例中，实例中为true

delete person1.name ;       //delete只会删除实例的属性/方法 不会删除原型

console.info(person1.hasOwnProperty("name")); //false

console.info(person1.name); //Je

//ex3.2 更简单的原型方法

function Person(){

}

Person.prototype = {

constructor : Person,          //默认下不再指向Person,有必要可以在这添加,但[Enumerable]属性变为true,默认为false;

name : 'je',

age : '29',

job : 'student',

sayName : function(){

console.info(this.name);

}

}

console.info(Object.keys(Person.prototype));  //["constructor", "name", "age", "job", "sayName"]

//ex3.3 constructor的Enumerable属性

function Person(){

}

Person.prototype = {

name : 'je',

age : '29',

job : 'student',

sayName : function(){

console.info(this.name);

}

}

//重设构造函数，只适用ECMA5兼容的浏览器

Object.defineProperty(Person.prototype,"constructor",{

enumerable : false,

value : Person

});

console.info(Object.keys(Person.prototype)); //["name", "age", "job", "sayName"]

//ex4 组合使用构造函数模式和原型模式

function Person(name,age,job){

this.name = name;

this.age = age;

this.job = job;

this.friends = ["je","no"];

}

Person.prototype = {

constructor : Person,

sayName : function(){

console.info(this.name);

}

}

var person1 = new Person("je",18,"stu");

var person2 = new Person("ni",20,"st");

person1.friends.push("ke");

console.info(person1.friends);  //["je", "no", "ke"]

console.info(person2.friends); //["je", "no"]

console.info(person1.sayName==person2.sayName); //true

//ex 5 动态原型模式

function Person(name,age,job){

this.name = name;

this.age = age;

this.job = job;

//方法

if(typeof this.sayName != "function"){

Person.prototype.sayName = function(){

console.info(this.name);

}

}

}

//ex 6 寄生构造函数--不能使用instanceof 确定对象类型

function Person(name,age,job){

var o = new Object();

o.name = name;

o.age = age;

o.job = job;

o.sayName = function(){

console.info(this.name);

}

return o;

}

var friend = new Person("je",18,"stu");

friend.sayName(); //je

//ex 6.1

function SpecialArray(){

var values = new Array();

values.push.apply(values,arguments);

values.toPipedString = function(){

return this.join("|");

}

return values;

}

var color = new SpecialArray("red","blue","green");

console.info(color.toPipedString());  //red|blue|green

//ex 7 稳妥构造函数--不用this和new ,instanceof没用

function Person(name,age,job){

var o = new Object();

o.name = name;

o.age = age;

o.job = job;

o.sayName = function(){

console.info(name);

}

return o;

}

var friend = Person("je",18,"stu");

friend.sayName(); //je

//ex 8 原型链

function Supertype(){

this.property = true;

}

Supertype.prototype.getSuperValue = function(){

return this.property;

};

function Subtype(){

this.subproperty = false;

}

//继承Supertype

Subtype.prototype = new Supertype();

Subtype.prototype.getSubvalue = function(){

return this.subproperty;

}

var instance = new Subtype();

console.info(instance.getSuperValue()); //true

//ex 8.1

function Supertype(){

this.property = true;

}

Supertype.prototype.getSuperValue = function(){

return this.property;

};

function Subtype(){

this.subproperty = false;

}

//继承Supertype

Subtype.prototype = new Supertype();

//添加新方法

Subtype.prototype.getSubvalue = function(){

return this.subproperty;

}

//重写超类中的方法

Subtype.prototype.getSuperValue=function(){

return false;

}

var test = new Supertype();

var instance = new Subtype();

console.info(instance.getSuperValue()); //false

console.info(test.getSuperValue());     //true

//ex 9借用构造函数

function Supertype(){

this.color = ["red","blue","green"];

}

function SubType(){

//继承Supertype

Supertype.call(this);

}

var instance1 = new SubType();

instance1.color.push("black");

console.info(instance1.color); //["red", "blue", "green", "black"]

var instance2 = new SubType();

console.info(instance2.color); //["red", "blue", "green"]