So siehts ganz gut aus !

node_modules/es5-ext/test/error/is-error.js

@@ -0,0 +1,18 @@
+"use strict";
+
+module.exports = function (t, a) {
+	a(t(), false, "Undefined");
+	a(t(1), false, "Primitive");
+	a(t({}), false, "Objectt");
+	a(t({ toString: function () {
+ return "[object Error]";
+} }), false,
+		"Fake error");
+	a(t(new Error()), true, "Error");
+	a(t(new EvalError()), true, "EvalError");
+	a(t(new RangeError()), true, "RangeError");
+	a(t(new ReferenceError()), true, "ReferenceError");
+	a(t(new SyntaxError()), true, "SyntaxError");
+	a(t(new TypeError()), true, "TypeError");
+	a(t(new URIError()), true, "URIError");
+};