application_helper.rb

module ApplicationHelper

  ACTIVE = {
    welcome:  [ { welcome: %w(index                         ) }  ],
    new_book: [ { books:   %w(new create                    ) }  ],
    books:    [ { books:   %w(index edit show update destroy) }, ],
  }

  def hl(key)
    actives = ACTIVE[key] || []
    controllers = []
    actions     = []
    actives.each do |item|
      item.each do |controller, actions|
        if controller_name == controller.to_s && actions.include?(action_name)
          return lambda { true }
        end
      end
    end
    return lambda { false }
  end
end