diff --git a/knockout/tests/knockout-tests.ts b/knockout/tests/knockout-tests.ts
index e2fbf4c02..b0755c12a 100644
--- a/knockout/tests/knockout-tests.ts
+++ b/knockout/tests/knockout-tests.ts
@@ -260,7 +260,7 @@ interface KnockoutExtenders {
 }
 
 interface KnockoutObservableArrayFunctions {
-    filterByProperty(propName, matchValue): KnockoutComputed;
+    filterByProperty(propName, matchValue): KnockoutComputed<any>;
 }
 
 declare var validate;