封装new操作符

一般情况下，我们这样创建实例

function Student(name) {
    this.name = name;
}

Student.prototype.hello = function () {
    alert('Hello, ' + this.name + '!');
};

var xiaoming=new Student('小明');
console.log(xiaoming.name)

封装之后

function Student(name) {
    this.name = name;
}

Student.prototype.hello = function () {
    alert('Hello, ' + this.name + '!');
};

function createSrudent(name){
    return new Student(name)
};
var xiaoming=createSrudent("小明")
console.log(xiaoming.name)