node.js裝飾者模式介紹

這篇文章主要介紹了node.js實現的裝飾者模式,簡單說明了裝飾者模式的原理、功能並結合實例形式給出了node.js裝飾者模式的實現方法,需要的朋友可以參考下

本文實例講述了node.js實作的裝飾者模式。分享給大家供大家參考，具體如下：

裝飾者模式的實作更強調類別的組合而不是透過繼承。這樣可以增強靈活性。在node.js 中，可以透過call函數實作。 call函數可以在一個物件中呼叫另一個類別的成員函數，從這種意義上達成類別的組合目的。

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());

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