From 75c91df43cafaacf7b9ad11cabb7329edede2b20 Mon Sep 17 00:00:00 2001
From: kwolfy <kwolfy11@gmail.com>
Date: Thu, 23 Nov 2017 09:48:36 +0300
Subject: [PATCH 1/3] instance extends feature

---
 src/common.js      |  9 +++++++++
 test/debug_spec.js | 26 ++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/src/common.js b/src/common.js
index 61eaf893..71e6cb3b 100644
--- a/src/common.js
+++ b/src/common.js
@@ -123,6 +123,7 @@ module.exports = function setup(env) {
     debug.useColors = createDebug.useColors();
     debug.color = selectColor(namespace);
     debug.destroy = destroy;
+    debug.extend = extend;
     //debug.formatArgs = formatArgs;
     //debug.rawLog = rawLog;
 
@@ -146,6 +147,14 @@ module.exports = function setup(env) {
     }
   }
 
+  function extend (namespace, delimiter) {
+    if(typeof delimiter === 'undefined') {
+      delimiter = ':';
+    }
+
+    return createDebug(this.namespace + delimiter + namespace);
+  }
+
   /**
    * Enables a debug mode by namespaces. This can include modes
    * separated by a colon and wildcards.
diff --git a/test/debug_spec.js b/test/debug_spec.js
index 142fbe79..7ac6d7cd 100644
--- a/test/debug_spec.js
+++ b/test/debug_spec.js
@@ -64,4 +64,30 @@ describe('debug', function () {
     });
   });
 
+
+  describe('extend namespace', function () {
+    var log;
+
+    beforeEach(function () {
+      debug.enable('foo');
+      log = debug('foo');
+    });
+
+    it('should extend namespace', function () {
+      var logBar = log.extend('bar');
+      expect(logBar.namespace).to.be.equal('foo:bar');
+    });
+
+    it('should extend namespace with custom delimiter', function () {
+      var logBar = log.extend('bar', '--');
+      expect(logBar.namespace).to.be.equal('foo--bar');
+    });
+
+    it('should extend namespace with empty delimiter', function () {
+      var logBar = log.extend('bar', '');
+      expect(logBar.namespace).to.be.equal('foobar');
+    });
+
+  });
+
 });

From 2698a6ccd2281e3e99db9678acd7839cd01093e7 Mon Sep 17 00:00:00 2001
From: kwolfy <kwolfy11@gmail.com>
Date: Fri, 22 Jun 2018 08:45:31 +0300
Subject: [PATCH 2/3] add .extend documentation

---
 README.md     | 14 ++++++++++++++
 src/common.js |  6 +-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 8a3b70bf..1c6664ee 100644
--- a/README.md
+++ b/README.md
@@ -248,6 +248,20 @@ error('now goes to stdout via console.info');
 log('still goes to stdout, but via console.info now');
 ```
 
+## Extend
+You can simply extend debugger 
+```js
+const log = require('debug')('auth');
+
+//creates new debug instance with extended namespace
+const logSign = log.extend('sign');
+const logLogin = log.extend('login');
+
+log('hello'); // auth hello
+logSign('hello'); //auth:sign hello
+logLogin('hello'); //auth:login hello
+```
+
 ## Set dynamically
 
 You can also enable debug dynamically by calling the `enable()` method :
diff --git a/src/common.js b/src/common.js
index 71e6cb3b..51b3d52f 100644
--- a/src/common.js
+++ b/src/common.js
@@ -148,11 +148,7 @@ module.exports = function setup(env) {
   }
 
   function extend (namespace, delimiter) {
-    if(typeof delimiter === 'undefined') {
-      delimiter = ':';
-    }
-
-    return createDebug(this.namespace + delimiter + namespace);
+    return createDebug(this.namespace + (delimiter || ':') + namespace);
   }
 
   /**

From 35c03f2698d826537d3d597e6a18685c5d8041dd Mon Sep 17 00:00:00 2001
From: kwolfy <kwolfy11@gmail.com>
Date: Sun, 1 Jul 2018 22:47:46 +0300
Subject: [PATCH 3/3] allow empty delimiter in extend

---
 src/common.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/common.js b/src/common.js
index 51b3d52f..65713e4d 100644
--- a/src/common.js
+++ b/src/common.js
@@ -148,7 +148,7 @@ module.exports = function setup(env) {
   }
 
   function extend (namespace, delimiter) {
-    return createDebug(this.namespace + (delimiter || ':') + namespace);
+    return createDebug(this.namespace + (typeof delimiter !== 'undefined' ? delimiter : ':') + namespace);
   }
 
   /**