$elemMatch (projection ) does not work with a new mongodb 2.2

[skotchio]

In a new version on MongoDB we can use an $elemMatch projection operator to limit the response of a query to a single matching element of an array. http://docs.mongodb.org/manual/reference/projection/elemMatch/

But it seems doesn't work yet in mongoose 3 here is the example:

{
     _id: ObjectId(5), 
     items: [1,2,3,45,4,67,9,4]
}

  Folder.findOne({_id: Object(5)}, {items: {$elemMatch: {$in: [1,67,9]}}})
    .exec(function (err, doc) { 
   });

I'm expected to get the follows doc:

  {
     _id: ObjectId(5), 
     items: [1,67,9]
 }

But unfortunately what I'm getting is document with all items:

  {
     _id: ObjectId(5), 
     items: [1,2,3,45,4,67,9,4]
 }

[aheckmann]

ah, yes the documentation isn't quite right (going to update this in a sec).

whats its saying is that you can now use $elemMatch in your projection, that is, your field selection: https://gist.github.com/3640687