From f48ee1cc1ef5ed4ae3ef3c098a39d8807ea60008 Mon Sep 17 00:00:00 2001
From: vedant <vedanthande2244@gmail.com>
Date: Sat, 13 Sep 2025 20:27:08 +0530
Subject: [PATCH] Fix: Add type validation for sendStatus to prevent BigInt
 serialization error (#6756)

- Add type checking in sendStatus() method to throw TypeError for non-number inputs
- Prevents uncaught 'Do not know how to serialize a BigInt' error
- Add test coverage for BigInt status code input
- Maintains backward compatibility with existing error patterns

Fixes #6756
---
 lib/response.js        |  3 +++
 test/res.sendStatus.js | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/lib/response.js b/lib/response.js
index 7a2f0ecce56..873cd7af178 100644
--- a/lib/response.js
+++ b/lib/response.js
@@ -326,6 +326,9 @@ res.jsonp = function jsonp(obj) {
  */
 
 res.sendStatus = function sendStatus(statusCode) {
+  if (typeof statusCode !== 'number') {
+    throw new TypeError('Invalid status code: ' + statusCode);
+  }
   var body = statuses.message[statusCode] || String(statusCode)
 
   this.status(statusCode);
diff --git a/test/res.sendStatus.js b/test/res.sendStatus.js
index b244cf9d173..10ee0c77c80 100644
--- a/test/res.sendStatus.js
+++ b/test/res.sendStatus.js
@@ -40,5 +40,17 @@ describe('res', function () {
         .get('/')
         .expect(500, /TypeError: Invalid status code/, done)
     })
+
+    it('should raise error for BigInt status code', function (done) {
+      var app = express()
+
+      app.use(function (req, res) {
+        res.sendStatus(200n)
+      })
+
+      request(app)
+        .get('/')
+        .expect(500, /TypeError.*Invalid status code/, done)
+    })
   })
 })