Custom has many through association in mongo db

has_many_through.rb

module HasManyThrough
  extend ActiveSupport::Concern

  class_methods do
    def define_through associations = {}
      class_eval do
        associations.each do |model, through_model|
          model_name = model.to_s.underscore

          define_method "#{model_name}_ids" do
            eval("@#{model_name}_ids ||= #{through_model.to_s.underscore.pluralize}.distinct(:#{model_name}_id).compact")
          end

          define_method "#{model_name.pluralize}?" do
            eval("#{model_name}_ids.present? ? #{model.to_s}.in(id: #{model_name}_ids).count != 0 : false")
          end

          define_method "#{model_name.pluralize}" do
            eval("#{model_name}_ids.present? ? #{model.to_s}.in(id: #{model_name}_ids) : []")
          end
        end
      end
    end
  end
end

model-example.rb

# example model for using above module
# creating all model here 
class DeveloperSkill
  include Mongoid::Document
  include Mongoid::Timestamps
  
  belongs_to :skill
  belongs_to :developer
end

class Skill
  include Mongoid::Document
  include Mongoid::Enum
  # included the above module
  include HasManyThrough
  
  has_many :developer_skills, dependent: :destroy
  
  define_through({Developer: :DeveloperSkill})
  # above will provide virtual association like below
  # has_many :developers
end

class Developer
  include Mongoid::Document
  include Mongoid::Timestamps
  # included the above module
  include HasManyThrough
  
  has_many :developer_skills, dependent: :destroy
  
  define_through({Skill: :DeveloperSkill})
  # above will provide virtual association like below
  # has_many :skills
end