From cbfabad4c02e3edd26343db05b1b127a5bc9be77 Mon Sep 17 00:00:00 2001
From: Marceli Pawlinski <marceli@pawlinski.pl>
Date: Wed, 29 Jul 2026 20:27:06 +0100
Subject: [PATCH] fix: throw on invalid Date serialization instead of producing
 NaN string

new Date(undefined) (an invalid Date) was serialized as
'0NaN-NaN-NaNTNaN:NaN:NaN.NaN+NaN:NaN' which is meaningless
and harmful for Postgres queries. Now throws a clear error.

Closes #3318
---
 packages/pg/lib/utils.js             |  3 +++
 packages/pg/test/unit/utils-tests.js | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/packages/pg/lib/utils.js b/packages/pg/lib/utils.js
index 638b43970..e7b7af06f 100644
--- a/packages/pg/lib/utils.js
+++ b/packages/pg/lib/utils.js
@@ -54,6 +54,9 @@ const prepareValue = function (val, seen) {
       return Buffer.from(val.buffer, val.byteOffset, val.byteLength)
     }
     if (isDate(val)) {
+      if (isNaN(val.getTime())) {
+        throw new Error('Invalid Date value provided to query parameter')
+      }
       if (defaults.parseInputDatesAsUTC) {
         return dateToStringUTC(val)
       } else {
diff --git a/packages/pg/test/unit/utils-tests.js b/packages/pg/test/unit/utils-tests.js
index 5f75f6c2d..825b5580f 100644
--- a/packages/pg/test/unit/utils-tests.js
+++ b/packages/pg/test/unit/utils-tests.js
@@ -78,6 +78,18 @@ test('prepareValues: BC date prepared properly', function () {
   helper.resetTimezoneOffset()
 })
 
+test('prepareValues: invalid date throws error', function () {
+  assert.throws(function () {
+    utils.prepareValue(new Date(undefined))
+  }, /Invalid Date/)
+  assert.throws(function () {
+    utils.prepareValue(new Date(NaN))
+  }, /Invalid Date/)
+  assert.throws(function () {
+    utils.prepareValue(new Date('not a date'))
+  }, /Invalid Date/)
+})
+
 test('prepareValues: 1 BC date prepared properly', function () {
   helper.setTimezoneOffset(-330)