Angular：这个构造函数放在哪里？

Question

我找到了一个非常有用的教程，可以创建一个带参数的角度工厂。无论多么有用，都会出现打嗝。

下面，工厂创建一个function-object / constructor的实例。本教程的作者没有解释这个＆＃34;库存＆＃34;应该放置构造函数。

＆＃34;库存＆＃34;构造函数进入一个单独的文件，比如模块/ IFFE？

/*  WHERE DOES THIS INVENTORY OBJECT GO?? */
function Inventory($http, url, project_id) {
 /** The public method for getting the project price **/
 this.price = function(callback) {
      $http.get(url+"?project="+project_id)
            .success(function(value) {
               callback(value);
            });
   };
};

angular.factory('InventoryFactory',[
 '$http',
   /** This is the factory method that Angular will execute only ONCE **/
   function InventoryFactory($http) {
   /** This is the function that will be injected into the directive, and called multiple times by the programmer **/
   return function(url, product_id) {
       /** this is the new object that will be created and used by the programmer **/
       return new Inventory($http, url, product_id);
    };
 }]);

angular.directive('inventoryStatus',['InventoryFactory',function(InventoryFactory) {
 return {
    link: function($scope,$el,$attr) {
         var inventory =  InventoryFactory('/api/projects',$scope.project_id);
         inventory.price(function(value){
            $scope.price = value;
         });
      }
   }
}]);

提前致谢！