1 files changed, 1 insertions, 1 deletions
diff --git a/packages/instant/src/components/animations/slide_up_and_down_animation.tsx b/packages/instant/src/components/animations/slide_up_and_down_animation.tsx
index 2e8061a19..da34b7485 100644
--- a/packages/instant/src/components/animations/slide_up_and_down_animation.tsx
+++ b/packages/instant/src/components/animations/slide_up_and_down_animation.tsx
@@ -63,7 +63,7 @@ interface SlideUpAndDownState {
 }
 
 export class SlideUpAndDownAnimation extends React.Component<SlideUpAndDownAnimationProps, SlideUpAndDownState> {
-    private _timeoutId: number | undefined;
+    private _timeoutId?: number;
     constructor(props: SlideUpAndDownAnimationProps) {
         super(props);
         this._timeoutId = undefined;