diff --git a/packages/babel-helpers/src/helpers.js b/packages/babel-helpers/src/helpers.js
index d235cf3285..9212dfb2c2 100644
--- a/packages/babel-helpers/src/helpers.js
+++ b/packages/babel-helpers/src/helpers.js
@@ -396,8 +396,8 @@ helpers.objectSpread = helper("7.0.0-beta.0")`
 
   export default function _objectSpread(target) {
     for (var i = 1; i < arguments.length; i++) {
-      var source = (arguments[i] != null) ? arguments[i] : {};
-      var ownKeys = Object.keys(Object(source));
+      var source = (arguments[i] != null) ? Object(arguments[i]) : {};
+      var ownKeys = Object.keys(source);
       if (typeof Object.getOwnPropertySymbols === 'function') {
         ownKeys = ownKeys.concat(Object.getOwnPropertySymbols(source).filter(function(sym) {
           return Object.getOwnPropertyDescriptor(source, sym).enumerable;