From f5faf8618021fb73a756eae09e0ecb693ac5d7de Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 29 Apr 2025 11:17:38 +0200
Subject: [PATCH] Assert that `numberToString` is called with a number (issue
 19877)

*NOTE:* Given that this is an *internal* function, used only in the worker-thread, it's not clear to me that this is an entirely "necessary" change.
---
 src/core/core_utils.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/core/core_utils.js b/src/core/core_utils.js
index b23072d59..eef79cddd 100644
--- a/src/core/core_utils.js
+++ b/src/core/core_utils.js
@@ -632,6 +632,13 @@ function recoverJsURL(str) {
 }
 
 function numberToString(value) {
+  if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
+    assert(
+      typeof value === "number",
+      `numberToString - the value (${value}) should be a number.`
+    );
+  }
+
   if (Number.isInteger(value)) {
     return value.toString();
   }