So siehts ganz gut aus !

node_modules/core-js/modules/es6.date.to-string.js

@@ -0,0 +1,12 @@
+var DateProto = Date.prototype;
+var INVALID_DATE = 'Invalid Date';
+var TO_STRING = 'toString';
+var $toString = DateProto[TO_STRING];
+var getTime = DateProto.getTime;
+if (new Date(NaN) + '' != INVALID_DATE) {
+  require('./_redefine')(DateProto, TO_STRING, function toString() {
+    var value = getTime.call(this);
+    // eslint-disable-next-line no-self-compare
+    return value === value ? $toString.call(this) : INVALID_DATE;
+  });
+}