Extract links and type-related methods to their own module.

lib/active_model/serializer.rb

@@ -8,6 +8,8 @@ require 'active_model/serializer/caching'
 require 'active_model/serializer/configuration'
 require 'active_model/serializer/fieldset'
 require 'active_model/serializer/lint'
+require 'active_model/serializer/links'
+require 'active_model/serializer/type'
 
 # ActiveModel::Serializer is an abstract class that is
 # reified when subclassed to decorate a resource.
@@ -17,32 +19,10 @@ module ActiveModel
     include Associations
     include Attributes
     include Caching
+    include Links
+    include Type
     require 'active_model/serializer/adapter'
 
-    with_options instance_writer: false, instance_reader: false do |serializer|
-      serializer.class_attribute :_type, instance_reader: true
-      serializer.class_attribute :_links # @api private : links definitions, @see Serializer#link
-      self._links ||= {}
-    end
-
-    # Serializers inherit _attribute_mappings, _reflections, and _links.
-    # Generates a unique digest for each serializer at load.
-    def self.inherited(base)
-      base._links = _links.dup
-      super
-    end
-
-    # @example
-    #   class AdminAuthorSerializer < ActiveModel::Serializer
-    #     type 'authors'
-    def self.type(type)
-      self._type = type
-    end
-
-    def self.link(name, value = nil, &block)
-      _links[name] = block || value
-    end
-
     # @param resource [ActiveRecord::Base, ActiveModelSerializers::Model]
     # @return [ActiveModel::Serializer]
     #   Preferentially returns
@@ -148,12 +128,6 @@ module ActiveModel
       end
     end
 
-    # @api private
-    # Used by JsonApi adapter to build resource links.
-    def links
-      self.class._links
-    end
-
     protected
 
     attr_accessor :instance_options

lib/active_model/serializer/adapter/json_api.rb

@@ -208,7 +208,7 @@ module ActiveModel
         end
 
         def links_for(serializer)
-          serializer.links.each_with_object({}) do |(name, value), hash|
+          serializer._links.each_with_object({}) do |(name, value), hash|
             hash[name] =
               if value.respond_to?(:call)
                 link = Link.new(serializer)

lib/active_model/serializer/links.rb

@@ -0,0 +1,33 @@
+module ActiveModel
+  class Serializer
+    module Links
+      extend ActiveSupport::Concern
+
+      included do
+        with_options instance_writer: false, instance_reader: true do |serializer|
+          serializer.class_attribute :_links # @api private
+          self._links ||= {}
+        end
+
+        extend ActiveSupport::Autoload
+      end
+
+      module ClassMethods
+        def inherited(base)
+          super
+          base._links = _links.dup
+        end
+
+        # Define a link on a serializer.
+        # @example
+        #   link :self { "/posts/#{object.id}" }
+        # @example
+        #   link :self, "/user"
+        #
+        def link(name, value = nil, &block)
+          _links[name] = block || value
+        end
+      end
+    end
+  end
+end

lib/active_model/serializer/type.rb

@@ -0,0 +1,25 @@
+module ActiveModel
+  class Serializer
+    module Type
+      extend ActiveSupport::Concern
+
+      included do
+        with_options instance_writer: false, instance_reader: true do |serializer|
+          serializer.class_attribute :_type # @api private
+        end
+
+        extend ActiveSupport::Autoload
+      end
+
+      module ClassMethods
+        # Set the JSON API type of a serializer.
+        # @example
+        #   class AdminAuthorSerializer < ActiveModel::Serializer
+        #     type 'authors'
+        def type(type)
+          self._type = type
+        end
+      end
+    end
+  end
+end