So siehts ganz gut aus !

node_modules/core-js/modules/_enum-keys.js

@@ -0,0 +1,15 @@
+// all enumerable object keys, includes symbols
+var getKeys = require('./_object-keys');
+var gOPS = require('./_object-gops');
+var pIE = require('./_object-pie');
+module.exports = function (it) {
+  var result = getKeys(it);
+  var getSymbols = gOPS.f;
+  if (getSymbols) {
+    var symbols = getSymbols(it);
+    var isEnum = pIE.f;
+    var i = 0;
+    var key;
+    while (symbols.length > i) if (isEnum.call(it, key = symbols[i++])) result.push(key);
+  } return result;
+};