diff --git a/lib/jasmine-core/jasmine.js b/lib/jasmine-core/jasmine.js
index a298383d..369f663a 100644
--- a/lib/jasmine-core/jasmine.js
+++ b/lib/jasmine-core/jasmine.js
@@ -2989,16 +2989,20 @@ getJasmineRequireObj().matchersUtil = function(j$) {
       }
 
       var extraKeys = [];
-      for (var i in allKeys) {
-        if (!allKeys[i].match(/^[0-9]+$/)) {
-          extraKeys.push(allKeys[i]);
-        }
+      if (allKeys.length === 0) {
+          return allKeys;
+      }
+
+      for (var x = 0; x < allKeys.length; x++) {
+          if (!allKeys[x].match(/^[0-9]+$/)) {
+              extraKeys.push(allKeys[x]);
+          }
       }
 
       return extraKeys;
     }
   }
-  
+
   function has(obj, key) {
     return Object.prototype.hasOwnProperty.call(obj, key);
   }
diff --git a/src/core/matchers/matchersUtil.js b/src/core/matchers/matchersUtil.js
index db1545be..7f17d665 100644
--- a/src/core/matchers/matchersUtil.js
+++ b/src/core/matchers/matchersUtil.js
@@ -223,16 +223,20 @@ getJasmineRequireObj().matchersUtil = function(j$) {
       }
 
       var extraKeys = [];
-      for (var i in allKeys) {
-        if (!allKeys[i].match(/^[0-9]+$/)) {
-          extraKeys.push(allKeys[i]);
-        }
+      if (allKeys.length === 0) {
+          return allKeys;
+      }
+
+      for (var x = 0; x < allKeys.length; x++) {
+          if (!allKeys[x].match(/^[0-9]+$/)) {
+              extraKeys.push(allKeys[x]);
+          }
       }
 
       return extraKeys;
     }
   }
-  
+
   function has(obj, key) {
     return Object.prototype.hasOwnProperty.call(obj, key);
   }