JavaScript享元模式：原理、实现与性能对比

/**
   * 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(componet){
    this.componet = componet;
    this.action = function(methodName){
      var self = this;
      var method = componet[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.componet,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);