From 08d61e594d3427a6442195856939df7a8930c918 Mon Sep 17 00:00:00 2001
From: Raphael Abayomi <raphyabak@gmail.com>
Date: Tue, 25 Aug 2026 09:28:31 +0100
Subject: [PATCH 1/2] Respect NO_COLOR environment variable in the dev format

Fixes #302.

morgan('dev') always emitted ANSI color codes, with no way to disable
them, even though NO_COLOR (https://no-color.org/) is the widely
adopted convention for this and colored escape codes in logs can be a
real accessibility problem.

When NO_COLOR is set to a non-empty value, compile and use a plain,
escape-code-free variant of the dev format line instead of the colored
one, caching it the same way the colored variants are already cached.
---
 index.js       |  9 +++++++++
 test/morgan.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/index.js b/index.js
index 313f5dcb..7989f230 100644
--- a/index.js
+++ b/index.js
@@ -207,6 +207,15 @@ morgan.format('tiny', ':method :url :status :res[content-length] - :response-tim
  */
 
 morgan.format('dev', function developmentFormatLine (tokens, req, res) {
+  // NO_COLOR (https://no-color.org/): when present and not an empty
+  // string, regardless of its value, ANSI color codes must not be added
+  if (process.env.NO_COLOR) {
+    var plainFn = developmentFormatLine.plain || (developmentFormatLine.plain =
+      compile(':method :url :status :response-time ms - :res[content-length]'))
+
+    return plainFn(tokens, req, res)
+  }
+
   // get the status code if response written
   var status = headersSent(res)
     ? res.statusCode
diff --git a/test/morgan.js b/test/morgan.js
index 85d3b9a7..e8f93bfc 100644
--- a/test/morgan.js
+++ b/test/morgan.js
@@ -1474,6 +1474,38 @@ describe('morgan()', function () {
             .expect(200, cb)
         })
       })
+
+      describe('with NO_COLOR environment variable set', function () {
+        beforeEach(function () {
+          process.env.NO_COLOR = '1'
+        })
+
+        afterEach(function () {
+          delete process.env.NO_COLOR
+        })
+
+        it('should not emit any ANSI escape codes', function (done) {
+          var cb = after(2, function (err, res, line) {
+            if (err) return done(err)
+            assert.strictEqual(line.indexOf('\x1b'), -1)
+            assert.ok(/^GET \/ 200 \d+\.\d{3} ms - -$/.test(line), 'unexpected line: ' + line)
+            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 () {

From b834227129a71c57bb8df8783235c8136aec75ce Mon Sep 17 00:00:00 2001
From: Ulises Gascon <ulisesgascongonzalez@gmail.com>
Date: Wed, 26 Aug 2026 18:03:30 +0200
Subject: [PATCH 2/2] docs: document NO_COLOR support in the dev format

---
 README.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/README.md b/README.md
index 5c61bc78..9f4e5ebd 100644
--- a/README.md
+++ b/README.md
@@ -168,6 +168,10 @@ for information codes.
 GET /dev 200 0.224 ms - 2
 ```
 
+Set the `NO_COLOR` environment variable to a non-empty value to disable the
+colored output (see [no-color.org](https://no-color.org/)). The same fields are
+then printed without any ANSI escape sequences.
+
 ##### short
 
 Shorter than default, also including response time.