Given a websites collection with a document

{ _id: 0, domain: "mongodb.org", "like": [1, 2, 3, 4, 5] }

where like represents the ids of all users who have "liked" the document,

Allow a query such as:

db.websites.find(

{ domain : "mongodb.org'' }

, { like : {$in : [4, 5, 6] } } );

resulting in

{ _id:0, domain: "mongodb.org", "like": [4, 5] }

Currently, the only way to do this is to filter client side or store the data in a more normalized fashion.