diff --git a/src/interfaces.ts b/src/interfaces.ts
index 414a0b0..1ae39a1 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -95,7 +95,7 @@ export interface Selectors
 export interface SortingFields
 {
     datasFieldNb: number;
-    order?: "asc"|"desc"|undefined;
+    order: "asc"|"desc"|undefined;
     field2HTML() : void;
 }
 export interface SortingFunctions