diff --git a/types/js-cookie/index.d.ts b/types/js-cookie/index.d.ts
index 294177da18..7db1ed3f96 100644
--- a/types/js-cookie/index.d.ts
+++ b/types/js-cookie/index.d.ts
@@ -57,7 +57,7 @@ declare namespace Cookies {
         /**
          * Create a cookie
          */
-        set(name: string, value: string | T, options?: CookieAttributes): void;
+        set(name: string, value: string | T, options?: CookieAttributes): string | undefined;
 
         /**
          * Read cookie
diff --git a/types/js-cookie/js-cookie-tests.ts b/types/js-cookie/js-cookie-tests.ts
index 7560e6490d..f060b10a5a 100644
--- a/types/js-cookie/js-cookie-tests.ts
+++ b/types/js-cookie/js-cookie-tests.ts
@@ -1,5 +1,6 @@
 import Cookies = require("js-cookie");
 
+// $ExpectType string | undefined
 Cookies.set('name', 'value');
 Cookies.set('name', 'value', { expires: 7 });
 Cookies.set('name', 'value', { expires: new Date() });