diff --git a/packages/@react-facet/core/src/helpers/hasDefinedValue.ts b/packages/@react-facet/core/src/helpers/hasDefinedValue.ts
index a090d836..a89afb40 100644
--- a/packages/@react-facet/core/src/helpers/hasDefinedValue.ts
+++ b/packages/@react-facet/core/src/helpers/hasDefinedValue.ts
@@ -1,3 +1,3 @@
 import { NoValue, NO_VALUE, Value } from '../types'
 
-export const hasDefinedValue = (value: Value | NoValue) => value != null && value !== NO_VALUE
+export const hasDefinedValue = (value: Value | NoValue): value is Value => value != null && value !== NO_VALUE