module Ariadne::ClassNameHelper

def merge_class_names(*args)
  [].tap do |classes|
    args.each do |class_name|
      next if class_name.blank?
      case class_name
      when String
        classes << class_name
      else
        raise ArgumentError, "Expected String class name, got #{class_name.class}"
      end
    end
  end.join(" ")
end