From 3cea386b2c26abffb0d2acfd9584203126f7579c Mon Sep 17 00:00:00 2001
From: Peter Bacon Darwin <pete@bacondarwin.com>
Date: Fri, 13 Feb 2015 11:09:32 +0000
Subject: [PATCH] perf(ngOptions): only watch labels if a display expression is
 specified

---
 src/ng/directive/ngOptions.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/ng/directive/ngOptions.js b/src/ng/directive/ngOptions.js
index f6ec5f227c0b..55b8d42faa5d 100644
--- a/src/ng/directive/ngOptions.js
+++ b/src/ng/directive/ngOptions.js
@@ -267,10 +267,14 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
         Object.keys(values).forEach(function getWatchable(key) {
           var locals = getLocals(values[key], key);
-          var label = displayFn(scope, locals);
           var selectValue = getTrackByValue(values[key], locals);
           watchedArray.push(selectValue);
-          watchedArray.push(label);
+
+          // Only need to watch the displayFn if there is a specific label expression
+          if (match[2]) {
+            var label = displayFn(scope, locals);
+            watchedArray.push(label);
+          }
         });
         return watchedArray;
       }),