【读书笔记】对象创建摘录

//工厂模式
function createPerson(name, age, job){
    var o = new Object();
    o.name = name;
    o.age = age;
    o.job = job;
    o.sayName = function(){
        alert(this.name);
    }
    return o;
}
function createPerson(name, age, job){
    return {
        name:name,
        age:age,
        job:job,
        sayName:function(){
            alert(this.name);
        }
    }
}

//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);
    }
    //每个对象的sayName都是不同的函数  解决办法：sayName用一个全局函数赋值
}

//String.startsWith
String.prototype.startsWith = function(text){
    return this.indexOf(text) == 0;
}

//原型模式
function Person(){}
Person.prototype = {
    constructor:Person,
    name:"default",
    age:0,
    job:"coder",
    friends:["jim","jack"],//所有实例共享这个属性，修改一个对所有实例生效，如果其他实例没有覆盖这个属性的话
    sayName:function(){
        alert(this.name);
    }
}

//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 = ["Shelby", "Court"];
}
Person.prototype = {
    constructor:Person,
    sayName:function(){
        alert(this.name);
    }
}

//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(){
            alert(this.name);
        }
    }//不能使用字面量来重写原型，否则会切断现有实例与新原型的联系
}