自调用构造函数

constructor.js

//自调用构造函数
function Waffle() {
    if (!(this instanceof Waffle)) {
        return new Waffle();
    }
    this.tastes = "yummy";
}

var first = new Waffle(),
    second = Waffle();
console.log(first.tastes);
console.log(second.tastes);