diff --git a/packages/netlify-cms-core/index.d.ts b/packages/netlify-cms-core/index.d.ts
index cd5631e9..7e5ac0f6 100644
--- a/packages/netlify-cms-core/index.d.ts
+++ b/packages/netlify-cms-core/index.d.ts
@@ -303,7 +303,7 @@ declare module 'netlify-cms-core' {
 
   export interface CmsSortableFieldsDefault {
     field: string;
-    direction: SortDirection;
+    direction?: SortDirection;
   }
   
   export interface CmsSortableFields {
diff --git a/packages/netlify-cms-core/src/interface.ts b/packages/netlify-cms-core/src/interface.ts
index cbe1c5a4..84d85587 100644
--- a/packages/netlify-cms-core/src/interface.ts
+++ b/packages/netlify-cms-core/src/interface.ts
@@ -572,7 +572,7 @@ export enum SortDirection {
 
 export interface CmsSortableFieldsDefault {
   field: string;
-  direction: SortDirection;
+  direction?: SortDirection;
 }
 
 export interface CmsSortableFields {