serializer.cr

class GroupTest
  include CrSerializer

  property user_id : Int32 = 999

  @[CrSerializer::Options(groups: ["admin"])]
  property admin_id : Int32 = 123

  @[CrSerializer::Options(groups: ["admin", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["admin"])]
  property admin_id : Int32 = 123

  @[CrSerializer::Options(groups: ["admin", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["admin"])]
  property admin_id : Int32 = 123

  @[CrSerializer::Options(groups: ["admin", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
  
  @[CrSerializer::Options(groups: ["apiv1", "default"])]
  property other_id : Int32 = 7777
end

GroupTest.new.to_json                       # => {"user_id":999,"other_id":7777}
GroupTest.new.to_json ["admin"]             # => {"admin_id":123,"other_id":7777}
GroupTest.new.to_json ["admin", "default"]  # => {"user_id":999,"admin_id":123,"other_id":7777}