diff --git a/typescript/core/base.ts b/typescript/core/base.ts
index b7c3ed83e..5902544bd 100644
--- a/typescript/core/base.ts
+++ b/typescript/core/base.ts
@@ -255,7 +255,7 @@ export interface _base {
 
     isNotEmptyArray: <T, U>(arr: T[] | U) => arr is [T, ...T[]];
 
-    isEmptyObject: (obj: any) => obj is object;
+    isEmptyObject: (obj: any) => boolean;
 
     isNotEmptyObject: (obj: any) => obj is object;