diff --git a/lib/api/global.d.ts b/lib/api/global.d.ts
index 2d542a88..05aefe2f 100644
--- a/lib/api/global.d.ts
+++ b/lib/api/global.d.ts
@@ -2,5 +2,5 @@ declare module 'await-to-js' {
   export default function to<T, U = Error>(
     promise: Readonly<Promise<T>>,
     errorExt?: object
-  ): Promise<[U | null, T | undefined]>;
+  ): Promise<[U, undefined] | [null, T]>;
 }