创建对象

工厂模式

缺陷：无法知道对象类型

console.log("工厂模式");
//无法识别对象
function createPerson(name, age, job){
	var o = new Object();
	o.name = name;
	o.age = age;
	o.sayName = function(){
		console.log(this.name);
	};
}
var person1 = createPerson("Nicholas", 29, "Software Engineer");
var person2 = createPerson("Greg", 27, "Doctor");

构造函数模式

缺点：方法不共享
new关键字会有以下4个步骤：
1)创建一个对象
2)将构造函数的作用域赋给新对象(因此this就指向该新对象)
3)执行构造函数中的代码
4)返回新对象

console.log("构造函数模式");
//方法不共享，都有自己的方法
function Person(name, age, job){
	this.name = name;
	this.age = age;
	this.job = job;
	this.sayName = function(){
		console.log(this.name);
	};
}
var person1 = new Person("Nicholas", 29, "Software Engineer");
var person2 = new Person("Greg", 27, "Doctor");
console.log(person1.constructor == Person); //true
console.log(person1 instanceof Object); //true
console.log(person1 instanceof Person); //true

原型模式

缺点：属性共享，属性不应该共享

console.log("原型模式");
//属性共享，属性不应该共享
function Person(){}
Person.prototype.name = "Nicholas";
Person.prototype.age = 29;
Person.prototype.job = "Software Engineer";
Person.prototype.sayName = function(){
	console.log(this.name);
};
var person1 = new Person();
person1.sayName();	//Nicholas
var person2 = new Person();
person2.sayName();	//Nicholas
console.log(person1.sayName == person2.sayName);	//true

组合使用构造模式和原型模式

认可度最高的一种模式

console.log("组合使用构造模式和原型模式");
//认同度最高的构造模式
function Person(name, age, job){
	this.name = name;
	this.age = age;
	this.job = job;
	this.friends = ["Shelby", "Court"];
}
Person.prototype = {
	// body...
	constructor:Person,
	sayName:function(){
		console.log(this.name);
	}
};
var person1 = new Person("Nicholas", 29, "Software Engineer");
var person2 = new Person("Greg", 27, "Doctor");
person1.friends.push("Van");
console.log(person1.friends);   //[ 'Shelby', 'Court', 'Van' ]
console.log(person2.friends);   //[ 'Shelby', 'Court' ]
console.log(person1.friends === person2.friends);   //false
console.log(person1.sayName === person2.sayName);   //true

动态原型模式

console.log("动态原型模式");
function Person(name, age, job){
	this.name = name;
	this.age = age;
	this.job = job;
	if (typeof this.sayName != "function"){
		Person.prototype.sayName = function() {
			// body...
			console.log(this.name);
		};
	}
}
var friend = new Person("Nicholas", 29, "Software Engineer");
friend.sayName();

寄生构造函数模式

>代码上和工厂方式区别小，方式上区别
console.log("寄生构造函数模式");
function Person(name, age, job){
	var o = new Object();
	o.name = name;
	o.age = age;
	o.job = job;
	o.sayName = function(){
		console.log(this.name);
	}
	return o;
}
var friend = new Person("Nicholas", 29 ,"Software Enginner");
friend.sayName();

稳妥构造函数模式

没有this关键字

console.log("稳妥构造函数模式");
function Person(name, age, job){
	var o = new Object();
	o.sayName = function(){
		console.log(name);
	};
	return o;
}