Trivial example of isolating Rails helper logic.rb

# In app/helpers/users_helper.rb

require_relative 'users_helper/greet'

module UsersHelper
  module Internals
  end
  private_constant :Internals
  include Internals

  def greet(user)
    UserLinkGreeting.new(self).greet(user)
  end
  # ...
end

# In app/helpers/users_helper/  greet.rb

module UsersHelper
  module Internals
    class UserLinkGreeting
      def initialize(helper_module)
        @h = helper_module
      end

      def greet(user)
        link_to "Hello, #{user.name}!", h.user_path(user)
      end

      private

      attr_reader :h
    end # end class UserLinkGreeting
  end
end