diff --git a/npm/ng-packs/packages/core/locale/src/utils/register-locale.ts b/npm/ng-packs/packages/core/locale/src/utils/register-locale.ts
index 1b2cdfcd3b..26003bf1c4 100644
--- a/npm/ng-packs/packages/core/locale/src/utils/register-locale.ts
+++ b/npm/ng-packs/packages/core/locale/src/utils/register-locale.ts
@@ -12,8 +12,8 @@ export interface LocaleErrorHandlerData {
 let localeMap = {};
 
 export interface RegisterLocaleData {
-  cultureNameLocaleFileMap: Record<string, string>;
-  errorHandlerFn: (data: LocaleErrorHandlerData) => any;
+  cultureNameLocaleFileMap?: Record<string, string>;
+  errorHandlerFn?: (data: LocaleErrorHandlerData) => any;
 }
 
 export function registerLocale(