Cannot acces object from javascript

In my ASP.NET MVC application, in ..\Views\Shared_Layout.cshtml I have the following line of code:

> <script type="text/javascript" src="http://mycontrols.com/Scripts/MyConstants.js"></script>

File MyConstants.js contains below:

var MyConstants = function() {
   return {
       DataObject1: {
          MyEnum1: {
             Item0: 0,
             Item1: 1,
             Item3: 2
          }
       },
       DataObject2: {
          MyEnum2: {
             Item0: 0,
             Item1: 1,
             Item3: 2
          }
       }
   };
};

Now from my view (Index.cshtml) I am trying to access in javascript to an item from MyEnum1:

var myEnum = MyConstants.DataObject1.MyEnum1.Item1;

but it does not work, below the error en devtools in chrome:

jQuery.Deferred exception: Cannot read property 'MyEnum1'of undefined TypeError: Cannot read property 'MyEnum1' of undefined

MyConstants is a function which returns an object, so you need to invoke it:

var myEnum = MyConstants().DataObject1.MyEnum1.Item1; 

If you'd prefer to keep your current syntax to retrieve the value, then you need to convert MyConstants to an object:

var MyConstants = {
  DataObject1: {
    MyEnum1: {
      Item0: 0,
      Item1: 1,
      Item3: 2
    }
  },
  DataObject2: {
    MyEnum2: {
      Item0: 0,
      Item1: 1,
      Item3: 2
    }
  }
};