node.js实现的装饰者模式示例
(编辑：jimmy 日期: 2024/11/15 浏览：3 次 )
本文实例讲述了node.js实现的装饰者模式。分享给大家供大家参考，具体如下：
装饰者模式的实现更强调类的组合而不是通过继承。这样可以增强灵活性。在node.js 中，可以通过call函数实现。call函数可以在一个对象中调用另一个类的成员函数，从这种意义上达成类的组合目的。
var util = require('util');
var Beverage = function(){
var description = "Unkown Beverage"
this.getDescription = function(){
return description;
}
}
function Espresso(){
Beverage.call(this);
this.description = "Espresso";
}
util.inherits(Espresso, Beverage);
Espresso.prototype.cost = function(){
return 1.99;
}
function HouseBlend(){
Beverage.call(this);
this.description = "House Blend Coffee";
}
util.inherits(HouseBlend, Beverage);
HouseBlend.prototype.cost = function(){
return .89;
}
function Mocha(beverage){
this.beverage = beverage;
};
Mocha.prototype.getDescription = function(){
return this.beverage.getDescription() + ", Mocha";
}
Mocha.prototype.cost = function(){
return 0.20 + this.beverage.cost();
}
function Whip(beverage){
this.beverage = beverage;
};
Whip.prototype.getDescription = function(){
return this.beverage.getDescription() + ", Whip";
}
Whip.prototype.cost = function(){
return 0.40 + this.beverage.cost();
}
var beverage = new Espresso();
console.log(beverage.getDescription() + " $" + beverage.cost());
var beverage2 = new HouseBlend();
beverage2 = new Mocha(beverage2);
beverage2 = new Mocha(beverage2);
beverage2 = new Whip(beverage2);
console.log(beverage2.getDescription() + " $" + beverage2.cost());
希望本文所述对大家node.js程序设计有所帮助。
下一篇：JavaScript使用FileReader实现图片上传预览效果