mapreduce_sample.coffee

map = ->
  return unless this.users instanceof Array
  for user_id in this.users when !user_id.equals(current_user)
    emit(user_id, {interests_in_common: 1})

reduce = (user_id, emits) -> 
  result = {interests_in_common: 0}
  result.interests_in_common += emit.interests_in_common for emit in emits
  result