From 2dc203332bf67ff2d5ac369c15d9a18805b7e6ed Mon Sep 17 00:00:00 2001
From: Ryan W Tenney <ryan@10e.us>
Date: Tue, 5 Oct 2010 21:22:37 -0400
Subject: [PATCH] Changed `reduceRight` to avoid unnecessarily cloning an
 array. `toArray` returns the first argument unmodified if it passes
 `isArray`. So if `obj` passes `isArray`, call `slice` on it directly,
 otherwise use `toArray`.

---
 underscore.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/underscore.js b/underscore.js
index 3580b2e94..88042c84e 100644
--- a/underscore.js
+++ b/underscore.js
@@ -110,7 +110,7 @@
       if (context) iterator = _.bind(iterator, context);
       return obj.reduceRight(iterator, memo);
     }
-    var reversed = _.clone(_.toArray(obj)).reverse();
+    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
     return _.reduce(reversed, iterator, memo, context);
   };