From 13784cfc9f9ad8d9f6a28c2b1071f5d8a11c0afc Mon Sep 17 00:00:00 2001
From: SAY-5 <say.apm35@gmail.com>
Date: Tue, 14 Apr 2026 20:47:13 -0700
Subject: [PATCH] support NO_COLOR environment variable in dev format

The dev format now checks for the NO_COLOR environment variable
(https://no-color.org/) and omits ANSI escape codes when it is set.
This follows the community convention adopted by many CLI tools.

Fixes #302
---
 index.js       | 27 ++++++++++++++++---------
 test/morgan.js | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 10 deletions(-)

diff --git a/index.js b/index.js
index bb97912..16a8e87 100644
--- a/index.js
+++ b/index.js
@@ -186,20 +186,27 @@ morgan.format('dev', function developmentFormatLine (tokens, req, res) {
     ? res.statusCode
     : undefined
 
-  // get status color
-  var color = status >= 500 ? 31 // red
-    : status >= 400 ? 33 // yellow
-      : status >= 300 ? 36 // cyan
-        : status >= 200 ? 32 // green
-          : 0 // no color
+  // get status color (respect NO_COLOR env var)
+  var noColor = 'NO_COLOR' in process.env
+  var color = noColor ? 0
+    : status >= 500 ? 31 // red
+      : status >= 400 ? 33 // yellow
+        : status >= 300 ? 36 // cyan
+          : status >= 200 ? 32 // green
+            : 0 // no color
 
   // get colored function
-  var fn = developmentFormatLine[color]
+  var fn = developmentFormatLine[noColor ? 'nocolor' : color]
 
   if (!fn) {
-    // compile
-    fn = developmentFormatLine[color] = compile('\x1b[0m:method :url \x1b[' +
-      color + 'm:status\x1b[0m :response-time ms - :res[content-length]\x1b[0m')
+    if (noColor) {
+      // compile without ANSI escape codes
+      fn = developmentFormatLine['nocolor'] = compile(':method :url :status :response-time ms - :res[content-length]')
+    } else {
+      // compile with color
+      fn = developmentFormatLine[color] = compile('\x1b[0m:method :url \x1b[' +
+        color + 'm:status\x1b[0m :response-time ms - :res[content-length]\x1b[0m')
+    }
   }
 
   return fn(tokens, req, res)
diff --git a/test/morgan.js b/test/morgan.js
index 6557a2b..4c247d1 100644
--- a/test/morgan.js
+++ b/test/morgan.js
@@ -1352,6 +1352,61 @@ describe('morgan()', function () {
             .expect(200, cb)
         })
       })
+
+      describe('with NO_COLOR env var', function () {
+        before(function () {
+          process.env.NO_COLOR = ''
+        })
+
+        after(function () {
+          delete process.env.NO_COLOR
+          // clear cached format functions
+          delete morgan.dev.nocolor
+        })
+
+        it('should not include ANSI escape codes', function (done) {
+          var cb = after(2, function (err, res, line) {
+            if (err) return done(err)
+            assert.ok(line.indexOf('\x1b[') === -1, 'should not contain ANSI escape codes')
+            done()
+          })
+
+          var stream = createLineStream(function onLine (line) {
+            cb(null, null, line)
+          })
+
+          var server = createServer('dev', { stream: stream }, function (req, res, next) {
+            res.statusCode = 200
+            next()
+          })
+
+          request(server)
+            .get('/')
+            .expect(200, cb)
+        })
+
+        it('should still include status code and method', function (done) {
+          var cb = after(2, function (err, res, line) {
+            if (err) return done(err)
+            assert.ok(line.indexOf('GET') !== -1, 'should contain method')
+            assert.ok(line.indexOf('200') !== -1, 'should contain status')
+            done()
+          })
+
+          var stream = createLineStream(function onLine (line) {
+            cb(null, null, line)
+          })
+
+          var server = createServer('dev', { stream: stream }, function (req, res, next) {
+            res.statusCode = 200
+            next()
+          })
+
+          request(server)
+            .get('/')
+            .expect(200, cb)
+        })
+      })
     })
 
     describe('short', function () {