Suppose I create the following db/collection:

> use articles
> db.stores.insert( [ 
             {_id : 1, arr : ['abc xyz', 'def']}, 
             {_id : 2, arr : ['jadskf', 'ljh abc']}])
> db.stores.createIndex({"arr" : "text"})

I want to do text search over the arrays arr and obtain only the array elements that match the search.

For instance,

> db.stores.find({$text : {$search : "abc"}})
{ "_id" : 1, "arr" : [ "abc xyz", "def" ] }
{ "_id" : 2, "arr" : [ "jadskf", "ljh abc" ] }

Ideally I'd like to only obtain the first element of the arr in the first document: abc xyz and only the second element of the arr in the second document: ljh abc, and also the _id of the matched documents.

Note that what I want is not a simple projection of the arr element, but of the elements of the arr where the match occurred.