diff --git a/packages/x6/src/graph/options.ts b/packages/x6/src/graph/options.ts
index c04778f9f9b..67faa5fd3d5 100644
--- a/packages/x6/src/graph/options.ts
+++ b/packages/x6/src/graph/options.ts
@@ -111,7 +111,7 @@ export namespace Options {
     /**
      * Snap edge to the closest node/port in the given radius on dragging.
      */
-    snap: boolean | { radius: number; anchor: 'center' | 'bbox' }
+    snap: boolean | { radius: number; anchor?: 'center' | 'bbox' }
 
     /**
      * Specify whether connect to point on the graph is allowed.