So siehts ganz gut aus !

node_modules/core-js/library/modules/es6.function.has-instance.js

@@ -0,0 +1,13 @@
+'use strict';
+var isObject = require('./_is-object');
+var getPrototypeOf = require('./_object-gpo');
+var HAS_INSTANCE = require('./_wks')('hasInstance');
+var FunctionProto = Function.prototype;
+// 19.2.3.6 Function.prototype[@@hasInstance](V)
+if (!(HAS_INSTANCE in FunctionProto)) require('./_object-dp').f(FunctionProto, HAS_INSTANCE, { value: function (O) {
+  if (typeof this != 'function' || !isObject(O)) return false;
+  if (!isObject(this.prototype)) return O instanceof this;
+  // for environment w/o native `@@hasInstance` logic enough `instanceof`, but add this:
+  while (O = getPrototypeOf(O)) if (this.prototype === O) return true;
+  return false;
+} });