总结js创建对象的几种方式

一、new 操作符 + Object 创建对象

var person = new Object();
    person.name = "lisi";
    person.age = 21;
    person.family = ["lida","lier","wangwu"];
    person.say = function(){
        alert(this.name);
    }

二、字面式创建对象

var person ={
        name: "lisi",
        age: 21,
        family: ["lida","lier","wangwu"],
        say: function(){
            alert(this.name);
        }
    };

以上两种方法在使用同一接口创建多个对象时，会产生大量重复代码，为了解决此问题，工厂模式被开发。

三、工厂模式

function createPerson(name,age,family) {
    var o = new Object();
    o.name = name;
    o.age = age;
    o.family = family;
    o.say = function(){
        alert(this.name);
    }
    return o;
}

var person1 =  createPerson("lisi",21,["lida","lier","wangwu"]);   //instanceof无法判断它是谁的实例，只能判断他是对象，构造函数都可以判断出
var person2 =  createPerson("wangwu",18,["lida","lier","lisi"]);
console.log(person1 instanceof Object);                           //true

四、构造函数模式

function Person(name,age,family) {
    this.name = name;
    this.age = age;
    this.family = family;
    this.say = function(){
        alert(this.name);
    }
}
var person1 = new Person("lisi",21,["lida","lier","wangwu"]);
var person2 = new Person("lisi",21,["lida","lier","lisi"]);
console.log(person1 instanceof Object); //true
console.log(person1 instanceof Person); //true
console.log(person2 instanceof Object); //true
console.log(person2 instanceof Person); //true
console.log(person1.constructor);      //constructor 属性返回对创建此对象的数组、函数的引用

五、原型模式

function Person() {
}

Person.prototype.name = "lisi";
Person.prototype.age = 21;
Person.prototype.family = ["lida","lier","wangwu"];
Person.prototype.say = function(){
    alert(this.name);
};
console.log(Person.prototype);   //Object{name: 'lisi', age: 21, family: Array[3]}

var person1 = new Person();        //创建一个实例person1
console.log(person1.name);        //lisi

var person2 = new Person();        //创建实例person2
person2.name = "wangwu";
person2.family = ["lida","lier","lisi"];
console.log(person2);            //Person {name: "wangwu", family: Array[3]}
// console.log(person2.prototype.name);         //报错
console.log(person2.age);              //21

六、构造函数模式+原型模式（混合模式）

function Person(name,age,family){
    this.name = name;
    this.age = age;
    this.family = family;
}

Person.prototype = {
    constructor: Person,  //每个函数都有prototype属性，指向该函数原型对象，原型对象都有constructor属性，这是一个指向prototype属性所在函数的指针
    say: function(){
        alert(this.name);
    }
}

var person1 = new Person("lisi",21,["lida","lier","wangwu"]);
console.log(person1);
var person2 = new Person("wangwu",21,["lida","lier","lisi"]);
console.log(person2);

七、动态原型模式

function Student(name,age){
    this.name=name;
    this.age=age;
    if(typeof this.myName!="function"){//第一次进入
        Student.prototype.myName = function(){
            alert(this.name);                    
        };                    
    }
}
var student1_ = new Student('aaa',15);
student1_.myName();

八、寄生构造函数模式

function Student(name,age){
    var o = new Object();
    o.name=name;
    o.age=age;
    o.myName=function(){
        alert(this.name);
    };                    
    return o;
}
var student1_ = new Student('aaa',15);
student1_.myName();

//这种模式的基本思想是创建一个函数,该函数的作用仅仅是封装创建对象的代码，然后再返回新创建的对象。

九、稳妥构造函数模式

function Student(name,age){
    var o = new Object();
    var name=name;
    var age=age;
    o.myName=function(){
        alert(name);
    };
    return o; 
}
var student1_ = new Student('aaa',15);
student1_.myName();

//没有公共属性，而且其他方法也不用引用this的对象