diff --git a/types/vis/index.d.ts b/types/vis/index.d.ts
index 9967c35061..84ff769270 100644
--- a/types/vis/index.d.ts
+++ b/types/vis/index.d.ts
@@ -245,7 +245,7 @@ export interface TimelineOptions {
   multiselectPerGroup?: boolean;
   onAdd?: TimelineOptionsItemCallbackFunction;
   onAddGroup?: TimelineOptionsGroupCallbackFunction;
-  onInitialDrawComplete?: () => void;
+  onInitialDrawComplete?: (() => void);
   onUpdate?: TimelineOptionsItemCallbackFunction;
   onMove?: TimelineOptionsItemCallbackFunction;
   onMoveGroup?: TimelineOptionsGroupCallbackFunction;