JavaScript设计模式之享元模式实例详解

/**
* 制造商
* 型号
* 拥有者
* 车牌号码
* 最近一次登记日期
*/
var Car = function(make,model,year,owner,tag,renewDate){
    this.make = make;
    this.model = model;
    this.year = year;
    this.owner = owner;
    this.tag = tag;
    this.renewDate = renewDate;
    this.getMake = function(){
      return this.make;
    }
}

//装饰者 .. 计算函数的耗时
var simpleProfiler = function(po){
    this.po = po;
    this.action = function(methodName){
      var self = this;
      var method = po[methodName];
      //如果是函数那就进行装饰
      if(typeof method == "function"){
        var startDate = new Date().getTime();//开始时间
        method.apply(self.po,arguments);
        var endDate = new Date();//结束时间
        alert(endDate - startDate);
      }
    }
}

var ca = new Array();
function addCar(){
    this.begin = function(){
      for (var i = 0; i < 4150000; i++) {
        ca.push(new Car("BMW","宝马","2017-10-18",
          "","GBMW88","2017-10-19"));
      }
    }
}
new simpleProfiler(new addCar()).action("begin")

/**
* 制造商
* 型号
* 拥有者
* 车牌号码
* 最近一次登记日期
*/
var Car = function(make,model,year){
    this.make = make;
    this.model = model;
    this.year = year;
    this.getMake = function(){
      return this.make;
    }
}

//单例模式的简单工厂
  var myCarInfo = function(){
    this.createCar = function(make,model,year,owner,tag,renewDate){
      var c = carInfoFactory(make,model,year);
      c["owner"] = owner;
      c["tag"] = tag;
      c["renewDate"] = renewDate;
      return c;
    }
  }
  var carInfoFactory = (function(){
    var carInfo = {};
    return function(make,model,year){
      if(carInfo[make+model+year]){
        return carInfo[make+model+year];
      }else{
        var newCar = new Car(make,model,year);
        carInfo[make+model+year] = newCar;
        return newCar;
        a
      }
    }
  })();

var test = new myCarInfo();
var startDate = new Date().getTime();
var ca = new Array();
for (var i = 0; i < 4150000; i++) {
    ca.push(test.createCar("BMW","宝马","2017-10-18",
          "","GBMW88","2017-10-19"))
}
var endDate = new Date();
alert(endDate - startDate);