Do not generate app/assets directory for api apps

railties/lib/rails/generators/rails/app/app_generator.rb

@@ -259,6 +259,12 @@ def create_vendor_files
         build(:vendor) unless options[:api]
       end
 
+      def delete_app_assets_if_api_option
+        if options[:api]
+          remove_dir 'app/assets'
+        end
+      end
+
       def delete_js_folder_skipping_javascript
         if options[:skip_javascript]
           remove_dir 'app/assets/javascripts'

railties/test/generators/api_app_generator_test.rb

@@ -74,7 +74,8 @@ def default_files
   end
 
   def skipped_files
-    %w(config/initializers/assets.rb
+    %w(app/assets
+       config/initializers/assets.rb
        config/initializers/cookies_serializer.rb
        config/initializers/session_store.rb
        vendor/assets