1 files changed, 62 insertions, 0 deletions
diff --git a/lib/api/helpers/packages/npm.rb b/lib/api/helpers/packages/npm.rb
new file mode 100644
index 00000000000..c1f6a001201
--- /dev/null
+++ b/lib/api/helpers/packages/npm.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+module API
+  module Helpers
+    module Packages
+      module Npm
+        include Gitlab::Utils::StrongMemoize
+        include ::API::Helpers::PackagesHelpers
+
+        NPM_ENDPOINT_REQUIREMENTS = {
+          package_name: API::NO_SLASH_URL_PART_REGEX
+        }.freeze
+
+        def endpoint_scope
+          params[:id].present? ? :project : :instance
+        end
+
+        def project
+          strong_memoize(:project) do
+            case endpoint_scope
+            when :project
+              user_project
+            when :instance
+              # Simulate the same behavior as #user_project by re-using #find_project!
+              # but take care if the project_id is nil as #find_project! is not designed
+              # to handle it.
+              project_id = project_id_or_nil
+
+              not_found!('Project') unless project_id
+
+              find_project!(project_id)
+            end
+          end
+        end
+
+        def project_or_nil
+          # mainly used by the metadata endpoint where we need to get a project
+          # and return nil if not found (no errors should be raised)
+          strong_memoize(:project_or_nil) do
+            next unless project_id_or_nil
+
+            find_project(project_id_or_nil)
+          end
+        end
+
+        def project_id_or_nil
+          strong_memoize(:project_id_or_nil) do
+            case endpoint_scope
+            when :project
+              params[:id]
+            when :instance
+              ::Packages::Package.npm
+                                .with_name(params[:package_name])
+                                .first
+                                &.project_id
+            end
+          end
+        end
+      end
+    end
+  end
+end