diff --git a/lib/helpers.js b/lib/helpers.js
index 0ac28b4d6a715e913da246f1b4b2576c7e5537f4..d048c0a9b498d08fb70337558fa541c1ecc2ed32 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -21,7 +21,7 @@ var _hasOwnProperty = Object.prototype.hasOwnProperty;
 function hasOwnProperty(obj, key) {
     return _hasOwnProperty.call(obj, key);
 }
-exports.hasOwnProperty = hasOwnProperty;
+Object.defineProperty(exports, "hasOwnProperty", { value: hasOwnProperty });
 function _objectKeys(obj) {
     if (Array.isArray(obj)) {
         var keys = new Array(obj.length);