//需要裝飾的類（函數(shù)）
function Macbook() {
 this.cost = function () {
  return 1000;
 };
} 
//計(jì)算商品的包裝費(fèi)
function PackagingFee(macbook) {
 this.cost = function () {
  return macbook.cost() + 75;
 };
}
//計(jì)算商品的運(yùn)費(fèi)
function Freight(macbook) {
 this.cost = function () {
  return macbook.cost() + 300;
 };
} 
//計(jì)算商品的保險(xiǎn)費(fèi)用
function Insurance(macbook) {
 this.cost = function () {
  return macbook.cost() + 250;
 };
}
// 用法
var myMacbook = new Insurance(new Freight(new PackagingFee(new Macbook())));
console.log(myMacbook.cost());//1625

// 用法
var myMacbook = new Insurance(new Freight(new PackagingFee(new Macbook())));
console.log(myMacbook.cost());//1625 
//上面的代碼等價(jià)于下面拆分后的代碼，或許拆分后代碼你更能看出前后的邏輯性
var macbook = new Macbook();
var package = new PackagingFee(macbook);
var freight = new Freight(package);
var myMacbook = new Insurance(freight);
//當(dāng)然，如果你不想聲明這么多變量（macbook、package、freight），只用一個(gè)變量也是可以的
var macbook = new Macbook();
macbook = new PackagingFee(macbook);
macbook = new Freight(macbook);
var myMacbook = new Insurance(macbook);

function ConcreteClass() {
 this.performTask = function () {
  this.preTask();
  console.log('doing something');
  this.postTask();
 };
}
function AbstractDecorator(decorated) {
 this.performTask = function () {
  decorated.performTask();
 };
}
function ConcreteDecoratorClass(decorated) {
 this.base = AbstractDecorator;
 this.base(decorated);// add performTask method
 decorated.preTask = function () {
  console.log('pre-calling..');
 };
 decorated.postTask = function () {
  console.log('post-calling..');
 };
}
var concrete = new ConcreteClass();
var decorator1 = new ConcreteDecoratorClass(concrete);
decorator1.performTask();
//pre-calling..
//doing something
//post-calling..

var concrete = new ConcreteClass(); //聲明一個(gè)變量concrete指向new出來(lái)的ConcreteClass對(duì)象
var decorator1 = new ConcreteDecoratorClass(concrete); //聲明一個(gè)變量decorator1指向new出來(lái)的ConcreteDecoratorClass對(duì)象，并傳入變量concrete作為形參

this.base = AbstractDecorator; //定義一個(gè)當(dāng)前對(duì)象（decorator1）的base屬性，并指向函數(shù)AbstractDecorator
this.base(decorated); //調(diào)用base屬性指向的函數(shù)，也就是調(diào)用AbstractDecorator函數(shù)，同時(shí)傳入形參decorated，形參decorated指向new出來(lái)的ConcreteClass對(duì)象

var tree = {};
tree.decorate = function () {
 console.log('Make sure the tree won\'t fall');
}; 
tree.getDecorator = function (deco) {
 tree[deco].prototype = this;
 return new tree[deco];
}; 
tree.RedApples = function () {
 this.decorate = function () {
  this.RedApples.prototype.decorate(); // 第7步：先執(zhí)行原型（這時(shí)候是Angel了）的decorate方法
  console.log('Add some red apples'); // 第8步 再輸出 red
  // 將這2步作為RedApples的decorate方法
 }
};
tree.BlueApples = function () {
 this.decorate = function () {
  this.BlueApples.prototype.decorate(); // 第1步：先執(zhí)行原型的decorate方法，也就是tree.decorate()
  console.log('Put on some blue apples'); // 第2步 再輸出blue
  // 將這2步作為BlueApples的decorate方法
 }
}; 
tree.Angel = function () {
 this.decorate = function () {
  this.Angel.prototype.decorate(); // 第4步：先執(zhí)行原型（這時(shí)候是BlueApples了）的decorate方法
  console.log('An angel on the top'); // 第5步 再輸出angel
  // 將這2步作為Angel的decorate方法
 }
};
tree = tree.getDecorator('BlueApples'); // 第3步：將BlueApples對(duì)象賦給tree，這時(shí)候父原型里的getDecorator依然可用
tree = tree.getDecorator('Angel'); // 第6步：將Angel對(duì)象賦給tree，這時(shí)候父原型的父原型里的getDecorator依然可用
tree = tree.getDecorator('RedApples'); // 第9步：將RedApples對(duì)象賦給tree
tree.decorate(); // 第10步：執(zhí)行RedApples對(duì)象的decorate方法
//Make sure the tree won't fall
//Add blue apples
//An angel on the top
//Put on some red apples

//tree.getDecorator('BlueApples')返回new出來(lái)的tree.BlueApples的實(shí)例對(duì)象，并將該對(duì)象賦值給空的tree對(duì)象
tree = tree.getDecorator('BlueApples'); //new出來(lái)的tree.BlueApples的實(shí)例對(duì)象的原型指向 --> 空對(duì)象tree 
//tree.getDecorator('Angel')返回new出來(lái)的tree.Angel的實(shí)例對(duì)象（這行代碼中的第二個(gè)tree已經(jīng)是上面一行代碼運(yùn)行結(jié)果后的tree.BlueApples的實(shí)例對(duì)象）
tree = tree.getDecorator('Angel'); //new出來(lái)的tree.Angel的實(shí)例對(duì)象的原型指向 --> tree.BlueApples的實(shí)例對(duì)象
//tree.getDecorator('RedApples')返回new出來(lái)的tree.RedApples的實(shí)例對(duì)象（這行代碼中的第二個(gè)tree已經(jīng)是上面一行代碼運(yùn)行結(jié)果后的tree.Angel的實(shí)例對(duì)象）
tree = tree.getDecorator('RedApples'); //new出來(lái)的tree.RedApples的實(shí)例對(duì)象的原型指向 --> tree.Angel的實(shí)例對(duì)象
//調(diào)用tree.decorate()，這里的tree已經(jīng)是new出來(lái)的tree.RedApples的實(shí)例對(duì)象了。
//tree.RedApples的實(shí)例對(duì)象的decorate屬性方法里面的第一行代碼是 “this.RedApples.prototype.decorate()”
//結(jié)合上面的分析可以得出以下的原型鏈結(jié)構(gòu)：
//this.RedApples.prototype --> tree.Angel;
//tree.Angel.prototype --> tree.BlueApples;
//tree.BlueApples.prototype --> 空對(duì)象tree
tree.decorate();