From 529c5b8abfa6679b29671edb7e02656304dd873a Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Thu, 29 Nov 2012 20:57:13 -0800
Subject: [PATCH] Use `forIn` in `_.isEqual` instead of `forOwn`.

Former-commit-id: dd057e421be029d67cd293b733ee1cfee2b7715f
---
 lodash.js | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/lodash.js b/lodash.js
index 077f208c0..08abcde27 100644
--- a/lodash.js
+++ b/lodash.js
@@ -1356,19 +1356,24 @@
       }
       return result;
     }
-    // deep compare objects
-    forOwn(a, function(value, key) {
-      // count the number of properties.
-      size++;
-      // deep compare each property value.
-      return (result = hasOwnProperty.call(b, key) && isEqual(value, b[key], stackA, stackB));
+    // deep compare objects using `forIn`, instead of `forOwn`, to avoid `Object.keys`
+    // which, in this case, is more costly
+    forIn(a, function(value, key, a) {
+      if (hasOwnProperty.call(a, key)) {
+        // count the number of properties.
+        size++;
+        // deep compare each property value.
+        return (result = hasOwnProperty.call(b, key) && isEqual(value, b[key], stackA, stackB));
+      }
     });
 
     if (result) {
       // ensure both objects have the same number of properties
-      forOwn(b, function() {
-        // `size` will be `-1` if `b` has more properties than `a`
-        return (result = --size > -1);
+      forIn(b, function(value, key, b) {
+        if (hasOwnProperty.call(b, key)) {
+          // `size` will be `-1` if `b` has more properties than `a`
+          return (result = --size > -1);
+        }
       });
     }
     return result;