node.js - Mongoose ODM: how to get first one and last five elements from array of embedded documents? -

i'm writing simple forum engine nodejs/express/mongodb , have little problem mongoose odm mongo.

i have board, thread , post models (a little bit simplified):

var boardschema = mongoose.schema({     _id: objectid, });   var threadschema = mongoose.schema({     _id: objectid,     board: {type: objectid, ref: 'board', index: true},     posts: [postschema], });   var postschema = mongoose.schema({     _id: objectid,     thread: {type: objectid, ref: 'thread'}, }); 

so posts embedded in thread documents. want display list of threads posts: first 1 , 5 latest ones. possible achieve in 1 query? can first or latest 5 using slice function, want more elegant 2 identical queries. here current query:

threadmodel     .find(         {board: boardid, is_deleted: false},          {posts: {$slice: -5}}     )     .sort({last_updated: 1, is_sticky: 1})     .skip(settings.threadsonpage * parseint(pagepointer, 10))     .limit(settings.threadsonpage)     .populate('board')     .exec(function(err, threads){         if (err) return callback(err);         if (threads === []) return callback(404);         callback(null, threads);     });