1 //两种简单创建对象的方式
2 var person = new Object ();
3 person.name = "nicholas";
4 person.age = 29;
5 person.job = "software engineer" ;
6 person.sayName = function () {
7 alert (this. name);
8 };
9 var person1 = {
10 name : "nicholas",
11 age : 29,
12 job : "software engineer",
13 sayName : function () {
14 alert (this. name);
15 }
16 };
//两种简单创建对象的方式
var person = new Object ();
person.name = "nicholas";
person.age = 29;
person.job = "software engineer" ;
person.sayName = function () {
alert (this. name);
};
var person1 = {
name : "nicholas",
age : 29,
job : "software engineer",
sayName : function () {
alert (this. name);
}
};
//两种简单创建对象的方式
var person = new Object ();
person.name = "nicholas";
person.age = 29;
person.job = "software engineer" ;
person.sayName = function () {
alert (this. name);
};
var person1 = {
name : "nicholas",
age : 29,
job : "software engineer",
sayName : function () {
alert (this. name);
}
};
属性类型
数据属性
Configurable:是否能删除（delete），默认true。
Enumerable:是否能枚举，默认true。
Writable:是否能更改，默认true。
Value:属性的字面类型。
var person = {} ;
Object.defineProperty(person , "name", {
writable : false,
value : "nicholas"
});
alert(person.name ); //nicholas
person.name= "greg"; //由于writable为false，设置无效。
alert(person.name ); //nicholas
var person = {} ;
Object.defineProperty(person , "name", {
configurable : false,
value : "nicholas"
});
alert(person.name ); //nicholas
delete person.name; //由于configurable为false，删除无效。
alert(person.name ); //nicholas
//抛出错误
Object.defineProperty(person , "name", {
configurable : true,
value: "hello"
});
访问器属性
Configurable:
Enumerable:
Get:读取属性时所需要用到的函数。默认为undefined。
Set:写入属性时所需要用到的函数。默认为undefined。
//访问器属性
var book = {
_year : 2004,
edition : 1
};
Object.defineProperty(book , "year", {
get : function () {
return this. _year;
} ,
set : function (val) {
if (val > 2004) {
this. _year = val;
this .edition++ ;
}
}
});
book.year= 2005;
alert(book.edition );
/在不支持ecmascript5（defineProperty方法）的浏览器中，定义setter，getter
book.__defineGetter__( "year",function (){
return this ._year;
});
book.__defineSetter__( "year",function (year){
if (year>2004){
this. _year=year;
this.edition ++;
}
});
工厂模式
//工厂模式
function createPerson(name, age,job){
var o={};
o. name=name;
o. age=age;
o. job=job;
o. sayName=function(){
alert (this. name);
}
return o;
}
var person1=createPerson( "nicholas",29 ,"software engineer") ;
var person2= createPerson("aa" ,22, "student");
构造函数模式
优缺点
/构造函数模式
function Person(name, age,job){
this .name=name ;
this.age =age;
this.job =job;
this.sayName =function(){
alert (this. name);
} ;
}
var person1=new Person ("nicholas", 29,"software engineer") ;
var person2= new Person( "aa",22 ,"student") ;
alert(person1.constructor ===Person) ; //true
alert(person1 instanceof Person ); //true
alert(person1 instanceof Object ); //true
//如果是工厂模式，为Object类型
ecmascript5中的Object.getPropertyDescriptor()方法只能用于实例属性，要取得原型属性的描述符，必须直接在原型对象上调用Object.getOwnPropertyDescriptor()方法。
原型方法
hasOwnProperty()方法，in 关键字。
//原型模式
function Person() {
}
Person.prototype .name = "nicholas";
Person.prototype .age = 29;
Person.prototype .job = "software engineer" ;
Person.prototype .sayName = function () {
alert (this. name);
}
var person1 = new Person ();
alert (person1.hasOwnProperty( "name")); //false
alert("name" in person1); //true
person1.name= "aa";
alert(person1.hasOwnProperty ("name")) ; //true
alert("name" in person1); //true
var prop= "name";
alert(hasPrototypeProperty (person1,prop)) ; //true
alert(hasPrototypeProperty2 (person1,prop)) ; //true
person1.name= "aa";
alert(hasPrototypeProperty (person1,prop)) ; //false
alert(hasPrototypeProperty2 (person1,prop)) ; //true
//简单判断是否是原型属性
function hasPrototypeProperty(obj, name){
return !obj.hasOwnProperty(name)&&(name in obj);
}
function hasPrototypeProperty2(obj, name){
var propVal,res= false;
if(obj.hasOwnProperty (name)){
propVal=obj[name];
delete obj[name];
}
if (name in obj){
res=true;
}
if (typeof propVal !== "undefined"){
obj[name]=propVal;
}
return res;
}
var keys= Object.keys( Person.prototype );
alert(keys); //name,age,job,sayName
var p1=new Person ();
p1.name= "p1name";
var p1keys= Object.keys(p1) ;
alert(p1keys); //name
var props= Object.getOwnPropertyNames( Person.prototype );
alert(props); //constructor,name,age,job,sayName
更简单的原型语法
//原型的简写形式
function Person() {
}
Person.prototype = {
constructor : Person, //重新赋值构造函数，此时的enumerable属性改变为true，
// 可通过Object.defineProperty()方法正确构造
age : 29,
job : "software engineer",
sayName : function () {
alert (this. name);
}
};
原型链
function SuperType (){
this .property= true;
}
SuperType .prototype. getSuperValue=function(){
return this .property;
};
function SubType(){
this .subproperty= false;
}
//原型链
SubType.prototype =new SuperType ();
SubType.prototype .getSubValue= function(){
return this .subproperty;
};
var instance= new SubType() ;
alert(instance.getSuperValue ()); //true
原型式继承
//原型式继承
function object (o){
function F (){}
F . prototype=o ;
return new F() ;
}
var person={
name : "nicholas",
friends :[ "shelby", "court" ,"van" ]
}
var person1= object(person) ;
person1. friends. push ("rob" ) ;
var person2= object (person);
person2. friends. push ("linda" ) ;
alert (person2.friends ) ;
组合使用构造模式和原型模式
//组合使用构造函数和原型模式
function Person(name, age,job){
this .name=name ;
this.age =age;
this.job =job;
this.friends =["shelby", "court"];
}
Person.prototype ={
constructor :Person,
sayName :function(){
alert (this. name);
}
};
var person1= new Person( "nicholas",29 ,"software engineer") ;
var person2= new Person( "greg",27 ,"doctor") ;
person1.sayName() ;
person2.sayName() ;
//组合继承
function SuperType(name){
this .name=name ;
this.colors =["red", "blue","green" ];
}
SuperType .prototype. sayName=function(){
alert (this. name);
}
function SubType(name, age){
SuperType .call( this, name);
this.age =age;
}
SubType.prototype =new SuperType ();
SubType.prototype .constructor= SubType;
SubType.prototype .sayAge= function(){
alert (this. age);
};
var instance1= new SubType( "nicholas",29 );
instance1. colors.push ("black") ;
alert(instance1.colors ); //red,blue,green,black
instance1. sayName(); //nicholas
instance1. sayAge(); //29
ecmascript5 中的Object.create()
//ecmascript5中的Object.create()与之类似;
//Object.create(proto,props);
var person1= Object. create (person);
person1. friends. push ("rob" ) ;
var person2= Object . create(person) ;
person2. friends. push ("linda" ) ;
var person3= Object . create(person , {
name :{
value : "greg"
}
});
person3. friends. push ("barbie" ) ;
alert (person2.friends ) ;
寄生组合式
//寄生组合式继承
function inheritPrototype (subType, superType){
var prototype= object(superType. prototype );
prototype. constructor =subType;
subType. prototype =prototype;
}
function SuperType (name){
this . name=name ;
this .colors =[ "red", "blue" ,"green" ] ;
}
SuperType . prototype. sayName = function(){
alert ( this. name );
} ;
function SubType(name , age){
SuperType . call( this, name) ;
this .age =age ;
}
inheritPrototype ( SubType, SuperType );
SubType .prototype . sayAge= function (){
alert ( this. age );
} ;
寄生构造函数
优缺点，
//寄生构造函数
function SpecialArray(){
var values=new Array ();
values. push.apply (values,arguments) ; //调用values属性的方法
values. toPipedString=function(){
return this. join("|" );
}
return values;
}
var colors=new SpecialArray ("red", "blue","yellow" );
alert(colors.toPipedString ()); //red|blue|yellow
寄生式继承
//寄生式继承
function createAnother(original){
var clone=object(original) ;
clone. sayHi=function(){
alert ("hi") ;
} ;
return clone;
}
var person1=createAnother(person) ;
person1.sayHi() ;
稳妥构造函数
稳妥对象，
//稳妥方法
function Person(name, age,job){
var o=new Object ();
//定义私有变量和属性
//添加方法
o. sayName=function(){
alert (name);
} ;
return o;
}
var person1=Person( "aa",22 ,"aaaa") ;
person1.sayName() ;
