diff --git a/types/is-date-object/index.d.ts b/types/is-date-object/index.d.ts
index 3ad24b15af..52b2f3ac84 100644
--- a/types/is-date-object/index.d.ts
+++ b/types/is-date-object/index.d.ts
@@ -4,10 +4,7 @@
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 3.3
 
-type InvalidTypes = undefined | null | boolean | string | number | [] | {};
-
 declare function isDateObject(value: Date): true;
-declare function isDateObject(value: InvalidTypes | unknown): boolean;
 declare function isDateObject(value?: object): boolean;
 declare function isDateObject(value?: null | undefined | boolean | string | number | symbol | bigint | Array | Function): false;