vue 啥几把

function proxy (target, sourceKey, key) {
  sharedPropertyDefinition.get = function proxyGetter () {
    return this[sourceKey][key]
  };
  sharedPropertyDefinition.set = function proxySetter (val) {
    this[sourceKey][key] = val;
  };
  Object.defineProperty(target, key, sharedPropertyDefinition);
}

    var that = this;

   var d = typeof(that.Id); //object

if(that.Id)  //调用这句 直接 进入 proxy 方法中     懵逼中 ................. 

{ alert(0); }