From d8e89900675163a0dc80979126a30f2648adb0e0 Mon Sep 17 00:00:00 2001
From: jkroso <jkroso@gmail.com>
Date: Fri, 24 May 2013 15:05:25 +1200
Subject: [PATCH] add .swap()

---
 index.js        | 13 +++++++++++++
 test/classes.js | 15 +++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/index.js b/index.js
index e3a30d5..16845b7 100644
--- a/index.js
+++ b/index.js
@@ -162,3 +162,16 @@ ClassList.prototype.contains = function(name){
     ? this.list.contains(name)
     : !! ~index(this.array(), name);
 };
+
+/**
+ * Swap `a` for `b`
+ *
+ * @param {String} a
+ * @param {String} b
+ * @return {ClassList}
+ * @api public
+ */
+
+ClassList.prototype.swap = function(a, b){
+  return this.remove(a).add(b);
+};
diff --git a/test/classes.js b/test/classes.js
index c9c7135..4bc51c6 100644
--- a/test/classes.js
+++ b/test/classes.js
@@ -92,4 +92,19 @@ describe('classes(el)', function(){
       assert(true === classes(el).has('there'));
     })
   })
+
+  describe('.swap(old, new)', function(){
+    it('should remove `old` and add `new`', function(){
+      el.className = 'old';
+      classes(el).swap('old', 'new');
+      assert('new' === el.className);
+    })
+
+    it('should\'t care if `old` doesn\'t exist', function(){
+      el.className = 'foo';
+      classes(el).swap('old', 'new');
+      assert(true === classes(el).has('foo'));
+      assert(false === classes(el).has('old'));
+    })
+  })
 })