From 96709b727fccc7b94ef2b31a02461edadf07f961 Mon Sep 17 00:00:00 2001
From: Joe Haddad <timer150@gmail.com>
Date: Mon, 19 Jun 2017 13:27:02 -0400
Subject: [PATCH] Fix a potential issue (#2569)

---
 packages/react-scripts/scripts/build.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/react-scripts/scripts/build.js b/packages/react-scripts/scripts/build.js
index aa95774f..2e4bc21e 100644
--- a/packages/react-scripts/scripts/build.js
+++ b/packages/react-scripts/scripts/build.js
@@ -112,7 +112,12 @@ function build(previousFileSizes) {
       if (messages.errors.length) {
         return reject(new Error(messages.errors.join('\n\n')));
       }
-      if (process.env.CI && process.env.CI.toLowerCase() !== 'false' && messages.warnings.length) {
+      if (
+        process.env.CI &&
+        (typeof process.env.CI !== 'string' ||
+          process.env.CI.toLowerCase() !== 'false') &&
+        messages.warnings.length
+      ) {
         console.log(
           chalk.yellow(
             '\nTreating warnings as errors because process.env.CI = true.\n' +