Before & After Ruby Metaprogramming

hierarchy_processor_after.rb

class HierarchyProcessor

  attr_reader :input, :user

  def initialize(input, user)
    raise ArgumentError, "user expected User, was #{ user.class }" unless user.is_a?(User)
    @input = JSON.parse(input)
    @user = user
  end

  [:service_groups, :locations, :roles, :employment_types].each do |type|
    define_method(type) do
      class_name = type.to_s.classify.constantize
      class_name.where(id: @input[type.to_s].map{ |s| s['id'] })
    end
  end

end

hierarchy_processor_before.rb

class HierarchyProcessor

  attr_reader :input, :user

  def initialize(input, user)
    raise ArgumentError, "user expected User, was #{ user.class }" unless user.is_a?(User)
    @input = JSON.parse(input)
    @user = user
  end

  def service_groups
    ServiceGroup.where(id: @input['service_groups'].map{ |s| s['id'] })
  end
  
  def locations
    Location.where(id: @input['locations'].map{ |s| s['id'] })
  end
  
  def roles
    Role.where(id: @input['roles'].map{ |s| s['id'] })
  end
  
  def employment_types
    EmploymentType.where(id: @input['employment_types'].map{ |s| s['id'] })
  end

end