From 66cdba3dfbc3cd71d891b805a35f592d05a684d0 Mon Sep 17 00:00:00 2001
From: Ben Newman <benjamn@fb.com>
Date: Tue, 8 Jul 2014 14:27:38 -0700
Subject: [PATCH] Avoid leading spaces when first argument to joinClasses is
 falsy.

This detail is going to become more important once the idiom
`className={joinClasses(this.props.className, newClass)}` becomes more
common, as it will when we move away from `this.transferPropsTo`.
---
 src/utils/joinClasses.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/utils/joinClasses.js b/src/utils/joinClasses.js
index f6a5c9e4d3..5e610cf933 100644
--- a/src/utils/joinClasses.js
+++ b/src/utils/joinClasses.js
@@ -35,7 +35,9 @@ function joinClasses(className/*, ... */) {
   if (argLength > 1) {
     for (var ii = 1; ii < argLength; ii++) {
       nextClass = arguments[ii];
-      nextClass && (className += ' ' + nextClass);
+      if (nextClass) {
+        className = (className ? className + ' ' : '') + nextClass;
+      }
     }
   }
   return className;