From 8aab64d26603f1ac4d38fccd6a301c83dbcb3cf0 Mon Sep 17 00:00:00 2001
From: Dustin Popp <dustinpopp@ibm.com>
Date: Tue, 25 Feb 2025 09:58:28 -0600
Subject: [PATCH] docs: add router debug log change to v5 migration guide

Signed-off-by: Dustin Popp <dustinpopp@ibm.com>
Co-authored-by: Sebastian Beltran <bjohansebas@gmail.com>
---
 en/guide/migrating-5.md | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/en/guide/migrating-5.md b/en/guide/migrating-5.md
index 7b2d5ee2ca..b907e86f78 100755
--- a/en/guide/migrating-5.md
+++ b/en/guide/migrating-5.md
@@ -39,6 +39,7 @@ You can then run your automated tests to see what fails, and fix problems accord
   <li><a href="#res.send.status">res.send(status)</a></li>
   <li><a href="#res.sendfile">res.sendfile()</a></li>
   <li><a href="#express.static.mime">express.static.mime</a></li>
+  <li><a href="#express:router-debug-logs">express:router debug logs</a></li>
 </ul>
 
 **Changed**
@@ -278,6 +279,25 @@ const mime = require('mime-types')
 mime.lookup('json')
 ```
 
+<h4 id="express:router-debug-logs">express:router debug logs</h4>
+
+In Express 5, router handling logic is performed by a dependency. Therefore, the
+debug logs for the router are no longer available under the `express:` namespace.
+In v4, the logs were available under the namespaces `express:router`, `express:router:layer`,
+and `express:router:route`. All of these were included under the namespace `express:*`.
+In v5.1+, the logs are available under the namespaces `router`, `router:layer`, and `router:route`.
+The logs from `router:layer` and `router:route` are included in the namespace `router:*`.
+To achieve the same detail of debug logging when using `express:*` in v4, use a conjunction of
+`express:*`, `router`, and `router:*`.
+
+```sh
+# v4
+DEBUG=express:* node index.js
+
+# v5
+DEBUG=express:*,router,router:* node index.js
+```
+
 <h3>Changed</h3>
 
 <h4 id="path-syntax">Path route matching syntax</h4>