From 825d35a2da0a9fa115baffea2f07d22b876332fc Mon Sep 17 00:00:00 2001
From: Josh Junon <josh@junon.me>
Date: Wed, 19 Dec 2018 04:56:06 +0100
Subject: [PATCH] copy custom logger to namespace extension (fixes #646)

---
 src/common.js | 4 +++-
 test.js       | 8 ++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/common.js b/src/common.js
index 0b6d0b64..2f82b8dc 100644
--- a/src/common.js
+++ b/src/common.js
@@ -143,7 +143,9 @@ function setup(env) {
 	}
 
 	function extend(namespace, delimiter) {
-		return createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		const newDebug = createDebug(this.namespace + (typeof delimiter === 'undefined' ? ':' : delimiter) + namespace);
+		newDebug.log = this.log;
+		return newDebug;
 	}
 
 	/**
diff --git a/test.js b/test.js
index 460f9759..f61e079b 100644
--- a/test.js
+++ b/test.js
@@ -70,6 +70,14 @@ describe('debug', () => {
 			const logBar = log.extend('bar', '');
 			assert.deepStrictEqual(logBar.namespace, 'foobar');
 		});
+
+		it('should keep the log function between extensions', () => {
+			const log = debug('foo');
+			log.log = () => {};
+
+			const logBar = log.extend('bar');
+			assert.deepStrictEqual(log.log, logBar.log);
+		});
 	});
 
 	describe('rebuild namespaces string (disable)', () => {