Maximum and minimum for MongoMapper

A small hack to get minimum/maximum functionality on MongoMapper, its not 100% secure(can be wrong when inserting twice at the same time etc), but good enought for our usecase

Usage

  User.maximum(:friend_count)
  User.minimum(:friend_count)

Code

module MongoMapper::Document::ClassMethods
  def maximum(column)
    first(:order => "#{column} desc").try(column)
  end

  def minimum(column)
    first(:order => "#{column} asc").try(column)
  end
end