gistfile1.coffee

async = require "async"
getUserFriends = (userName, next) ->

  handleUser = (err, user) ->
    return next(err)  if err?
    getFriendsById user.id, doAsync

  doAsync = (err, friends) ->
    return next(err)  if err?
    if user.type is "power user"
      async.map friends, getFriendsById, getFriendsOfFriends
    else
      next null, friends

  getFriendsOfFriends = (err, friendsOfFriends) ->
    i = 0

    while i < friendsOfFriends.length
      j = 0

      while j < friendsOfFriends[i].length
        friends.push friendsOfFriends[i][j]  unless friends.indexOf(friendsOfFriends[i][j]) is -1
        j++
      i++
    next null, friends

  getFriendsById = (userId, next) ->
    db.friends.find
      userId: userId
    , (err, friends) ->
      return next(err)  if err?
      next null, friends

  db.users.findOne
    name: userName
  , handleUser