diff --git a/types/kefir/index.d.ts b/types/kefir/index.d.ts
index 7d524b3dda..ea823f73ff 100644
--- a/types/kefir/index.d.ts
+++ b/types/kefir/index.d.ts
@@ -6,7 +6,7 @@
 
 /// <reference types="node" />
 
-export type ValueOfAnObservable<T extends Observable<any, any>> = T['']
+export type ValueOfAnObservable<T extends Observable<any, any>> = T[''];
 
 export interface Subscription {
     unsubscribe(): void;