diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 55e4561e8e967682828d68f9b7a4a4873aaa87f9..3c99932e7255df10e25206d9f62966dbc9b2b1dd 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1048,15 +1048,7 @@ def resource(*resources, &block)
               get :new
             end if parent_resource.actions.include?(:new)
 
-            member do
-              get :edit if parent_resource.actions.include?(:edit)
-              get :show if parent_resource.actions.include?(:show)
-              if parent_resource.actions.include?(:update)
-                patch :update
-                put   :update
-              end
-              delete :destroy if parent_resource.actions.include?(:destroy)
-            end
+            set_member_mappings_for_resource
           end
 
           self
@@ -1215,15 +1207,7 @@ def resources(*resources, &block)
               get :new
             end if parent_resource.actions.include?(:new)
 
-            member do
-              get :edit if parent_resource.actions.include?(:edit)
-              get :show if parent_resource.actions.include?(:show)
-              if parent_resource.actions.include?(:update)
-                patch :update
-                put   :update
-              end
-              delete :destroy if parent_resource.actions.include?(:destroy)
-            end
+            set_member_mappings_for_resource
           end
 
           self
@@ -1574,6 +1558,18 @@ def name_for_action(as, action) #:nodoc:
               end
             end
           end
+
+          def set_member_mappings_for_resource
+            member do
+              get :edit if parent_resource.actions.include?(:edit)
+              get :show if parent_resource.actions.include?(:show)
+              if parent_resource.actions.include?(:update)
+                patch :update
+                put   :update
+              end
+              delete :destroy if parent_resource.actions.include?(:destroy)
+            end
+          end
       end
 
       # Routing Concerns allow you to declare common routes that can be reused