From 086f3bc2052a1e56bfd98d8ec48721b9b632fab3 Mon Sep 17 00:00:00 2001
From: Varun <varunkulkarni13@gmail.com>
Date: Fri, 1 May 2026 11:53:24 -0400
Subject: [PATCH] fix(eio): make _query optional in EngineRequest

---
 packages/engine.io/lib/transport.ts        | 6 +++---
 packages/engine.io/lib/transports/index.ts | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/engine.io/lib/transport.ts b/packages/engine.io/lib/transport.ts
index 6d3b9cbf62..8b127e400b 100644
--- a/packages/engine.io/lib/transport.ts
+++ b/packages/engine.io/lib/transport.ts
@@ -13,7 +13,7 @@ function noop() {}
 type ReadyState = "open" | "closing" | "closed";
 
 export type EngineRequest = IncomingMessage & {
-  _query: Record<string, string>;
+  _query?: Record<string, string>;
   res?: ServerResponse;
   cleanup?: Function;
   websocket?: WebSocket & {
@@ -89,9 +89,9 @@ export abstract class Transport extends EventEmitter {
    *
    * @param {EngineRequest} req
    */
-  constructor(req: { _query: Record<string, string> }) {
+  constructor(req: { _query?: Record<string, string> }) {
     super();
-    this.protocol = req._query.EIO === "4" ? 4 : 3; // 3rd revision by default
+    this.protocol = req._query?.EIO === "4" ? 4 : 3; // 3rd revision by default
     this.parser = this.protocol === 4 ? parser_v4 : parser_v3;
     this.supportsBinary = !(req._query && req._query.b64);
   }
diff --git a/packages/engine.io/lib/transports/index.ts b/packages/engine.io/lib/transports/index.ts
index 47b3f17be1..cdb04707a1 100644
--- a/packages/engine.io/lib/transports/index.ts
+++ b/packages/engine.io/lib/transports/index.ts
@@ -14,7 +14,7 @@ export default {
  * Polling polymorphic constructor.
  */
 function polling(req: EngineRequest) {
-  if ("string" === typeof req._query.j) {
+  if ("string" === typeof req._query?.j) {
     return new JSONP(req);
   } else {
     return new XHR(req);