Move id and json_api_type methods from Serializer to JsonApi.

lib/active_model/serializer.rb

@@ -146,18 +146,6 @@ module ActiveModel
       @root || object.class.model_name.to_s.underscore
     end
 
-    def id
-      object.id if object
-    end
-
-    def json_api_type
-      if config.jsonapi_resource_type == :plural
-        object.class.model_name.plural
-      else
-        object.class.model_name.singular
-      end
-    end
-
     def attributes(options = {})
       attributes =
         if options[:fields]
@@ -166,8 +154,6 @@ module ActiveModel
           self.class._attributes.dup
         end
 
-      attributes += options[:required_fields] if options[:required_fields]
-
       attributes.each_with_object({}) do |name, hash|
         unless self.class._fragmented
           hash[name] = send(name)