Merge 7d1f4ea into 2758cfb

index.js

@@ -1,42 +1,52 @@
 'use strict';
 
+var isArray = Array.isArray;
+var keyList = Object.keys;
+var hasProp = Object.prototype.hasOwnProperty;
+
 module.exports = function equal(a, b) {
   if (a === b) return true;
 
-  var arrA = Array.isArray(a)
-    , arrB = Array.isArray(b)
-    , i;
+  var arrA = isArray(a)
+    , arrB = isArray(b)
+    , i
+    , length
+    , key;
 
   if (arrA && arrB) {
-    if (a.length != b.length) return false;
-    for (i = 0; i < a.length; i++)
+    length = a.length;
+    if (length != b.length) return false;
+    for (i = 0; i < length; i++)
       if (!equal(a[i], b[i])) return false;
     return true;
   }
 
   if (arrA != arrB) return false;
 
-  if (a && b && typeof a === 'object' && typeof b === 'object') {
-    var keys = Object.keys(a);
-    if (keys.length !== Object.keys(b).length) return false;
+  var dateA = a instanceof Date
+    , dateB = b instanceof Date;
+  if (dateA != dateB) return false;
 
-    var dateA = a instanceof Date
-      , dateB = b instanceof Date;
-    if (dateA && dateB) return a.getTime() == b.getTime();
-    if (dateA != dateB) return false;
+  var regexpA = a instanceof RegExp
+    , regexpB = b instanceof RegExp;
+  if (regexpA != regexpB) return false;
 
-    var regexpA = a instanceof RegExp
-      , regexpB = b instanceof RegExp;
-    if (regexpA && regexpB) return a.toString() == b.toString();
-    if (regexpA != regexpB) return false;
+  if (dateA && dateB) return a.getTime() == b.getTime();
+  if (regexpA && regexpB) return a.toString() == b.toString();
 
-    for (i = 0; i < keys.length; i++)
-      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;
+  if (a instanceof Object && b instanceof Object) {
+    var keys = keyList(a);
+    length = keys.length;
 
-    for (i = 0; i < keys.length; i++)
-      if(!equal(a[keys[i]], b[keys[i]])) return false;
+    for (i = 0; i < length; i++)
+      if (!hasProp.call(b, keys[i])) return false;
 
-    return true;
+    for (i = 0; i < length; i++) {
+      key = keys[i];
+      if (!equal(a[key], b[key])) return false;
+    }
+
+    return length == keyList(b).length;
   }
 
   return false;