diff --git a/typescript/core/platform/web/detectElementResize.ts b/typescript/core/platform/web/detectElementResize.ts
index c0ba6e28d..8e1566ce9 100644
--- a/typescript/core/platform/web/detectElementResize.ts
+++ b/typescript/core/platform/web/detectElementResize.ts
@@ -2,5 +2,5 @@ import { Widget } from "../../../core/widget";
 
 export type _DetectElementResize = {
   addResizeListener: (widget: Widget, fn: Function) => Function
-  removeResizeListener: (widget: Widget, fn: Function) => void
-}
\ No newline at end of file
+  removeResizeListener: (widget: Widget, fn?: Function) => void
+}