June 3, 2014 02:13 · Jun 3, 2014
diff --git a/nested_attributes_for_strategy.rb b/nested_attributes_for_strategy.rb
@@ -0,0 +1,32 @@
+class NestedAttributesForStrategy
+  def association(runner)
+    runner.run
+  end
+
+  def result(evaluation)
+    evaluation.object.tap do |instance|
+      evaluation.notify(:after_build, instance)
+      return attributes(instance)
+    end
+  end
+
+  private
+
+  def attributes(instance)
+    attrs = instance.attributes.delete_if do |k, _|
+      %w(id type created_at updated_at).include?(k)
+    end
+    nested_reflections(instance).each do |ref|
+      attrs.merge!("#{ref.name}_attributes" => instance.send(ref.name).map do |nested_obj|
+        attributes(nested_obj)
+      end)
+    end
+    attrs
+  end
+
+  def nested_reflections(instance)
+    instance.reflections.values.select do |ref|
+      ref.macro == :has_many && instance.respond_to?("#{ref.name}_attributes=")
+    end
+  end
+end