diff --git a/packages/engine.io-client/lib/globals.node.ts b/packages/engine.io-client/lib/globals.node.ts
index a39ce4b7f..535dc042f 100644
--- a/packages/engine.io-client/lib/globals.node.ts
+++ b/packages/engine.io-client/lib/globals.node.ts
@@ -82,7 +82,7 @@ export class CookieJar {
     });
   }
 
-  get cookies() {
+  get cookies(): IterableIterator<[string, Cookie]> {
     const now = Date.now();
     this._cookies.forEach((cookie, name) => {
       if (cookie.expires?.getTime() < now) {