So siehts ganz gut aus !

node_modules/core-js/modules/_create-property.js

@@ -0,0 +1,8 @@
+'use strict';
+var $defineProperty = require('./_object-dp');
+var createDesc = require('./_property-desc');
+
+module.exports = function (object, index, value) {
+  if (index in object) $defineProperty.f(object, index, createDesc(0, value));
+  else object[index] = value;
+};