diff --git a/packages/bun-framework-react/client/router.ts b/packages/bun-framework-react/client/router.ts
index 0cae351312..4a4eaa4a17 100644
--- a/packages/bun-framework-react/client/router.ts
+++ b/packages/bun-framework-react/client/router.ts
@@ -28,7 +28,7 @@ export class Router {
     this.cachedPages.set(id, page);
   }
 
-  async navigate(href: string, cacheId?: number): Promise<void> {
+  async navigate(href: string, cacheId: number | undefined): Promise<void> {
     const thisNavigationId = ++this.lastNavigationId;
     const olderController = this.lastNavigationController;