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); //trueconsole.log(person1 instanceof Object); //trueconsole.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(); //Nicholasvar person2 = new Person();person2.sayName(); //Nicholasconsole.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); //falseconsole.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;}