override handle_list method of ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder class

helper_method_builder.rb

class ActionDispatch::Routing::PolymorphicRoutes::HelperMethodBuilder

  # Extract from gems/actionpack-5.2.0/lib/action_dispatch/routing/polymorphic_routes.rb#HelperMethodBuilder class
  # @param [Array] list
  def handle_list(list)
    record_list = list.dup
    record      = record_list.pop

    args = []

    route = record_list.map { |parent|
      case parent
      when Symbol, String
        parent.to_s
      when Class
        args << parent
        parent.model_name.singular_route_key
      else
        args << parent.to_model
        parent.to_model.model_name.singular_route_key
      end
    }

    record_path = case record
                  when Symbol, String
                    record.to_s
                  when Class
                    @key_strategy.call record.model_name
                  else
                    model = record.to_model
                    if model.persisted?
                      args << model
                      model.model_name.singular_route_key
                    else
                      @key_strategy.call model.model_name
                    end
                  end

    # Custom here
    # when an array of two models is gave
    if list.size == 2 and list.all? {|o| o.is_a?(ActiveRecord::Base)}
      first_module = extract_module list.shift
      second_module = extract_module list.shift

      if first_module == second_module
        first_module = first_module.map(&:underscore).join('_')
        record_path.slice!(first_module  + '_')
      end

    end

    route << record_path
    # end of custom

    route << suffix

    named_route = prefix + route.join("_")
    [named_route, args]
  end

  private

  # @param [ActiveRecord] model
  # @return [Array]
  def extract_module(model)
    modules = model.class.name.split('::')
    modules.pop
    modules
  end
end