diff --git a/index.d.ts b/index.d.ts
index 04f7564695dd0bd2ed5ace66d0fd5838f53dbc62..0fdb6d9a06232b7af5dab1029c6fb4d3c4168c1e 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -118,12 +118,12 @@ export interface PlotScene {
 }
 
 export interface PlotRelayoutEvent extends Partial<Layout> {
-    "xaxis.range[0]"?: number | undefined;
-    "xaxis.range[1]"?: number | undefined;
-    "yaxis.range[0]"?: number | undefined;
-    "yaxis.range[1]"?: number | undefined;
-    "xaxis.autorange"?: boolean | undefined;
-    "yaxis.autorange"?: boolean | undefined;
+    "xaxis.range[0]"?: number;
+    "xaxis.range[1]"?: number;
+    "yaxis.range[0]"?: number;
+    "yaxis.range[1]"?: number;
+    "xaxis.autorange"?: boolean;
+    "yaxis.autorange"?: boolean;
 }
 
 export interface ClickAnnotationEvent {