From 989b41ccf8b0d3b15ebbabab6fb7ba2826a4bde5 Mon Sep 17 00:00:00 2001
From: Ian Clanton-Thuon <iclanton@users.noreply.github.com>
Date: Mon, 12 Jan 2026 14:17:30 -0500
Subject: [PATCH] Fix an issue with running npm commands.

---
 .../rush/fix-rush-publish_2026-01-12-19-17.json       | 11 +++++++++++
 libraries/rush-lib/src/utilities/Npm.ts               |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 common/changes/@microsoft/rush/fix-rush-publish_2026-01-12-19-17.json

diff --git a/common/changes/@microsoft/rush/fix-rush-publish_2026-01-12-19-17.json b/common/changes/@microsoft/rush/fix-rush-publish_2026-01-12-19-17.json
new file mode 100644
index 00000000000..efcd84c45fb
--- /dev/null
+++ b/common/changes/@microsoft/rush/fix-rush-publish_2026-01-12-19-17.json
@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "comment": "",
+      "type": "none",
+      "packageName": "@microsoft/rush"
+    }
+  ],
+  "packageName": "@microsoft/rush",
+  "email": "iclanton@users.noreply.github.com"
+}
\ No newline at end of file
diff --git a/libraries/rush-lib/src/utilities/Npm.ts b/libraries/rush-lib/src/utilities/Npm.ts
index 1e9c83627a9..c031831cd9e 100644
--- a/libraries/rush-lib/src/utilities/Npm.ts
+++ b/libraries/rush-lib/src/utilities/Npm.ts
@@ -19,7 +19,7 @@ async function runNpmCommandAndCaptureOutputAsync(
     captureExitCodeAndSignal: true
   });
 
-  if (signal !== undefined) {
+  if (signal) {
     throw new Error(`The npm command was terminated by signal: ${signal}. Output: ${stdout} ${stderr}`);
   } else if (exitCode !== 0) {
     throw new Error(`The npm command failed with exit code: ${exitCode}. Output: ${stdout} ${stderr}`);