npm and error messages

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

@@ -0,0 +1,12 @@
+"use strict";
+
+module.exports = function (t, a) {
+	var T = t, err = new T("My Error", "MY_ERROR", { errno: 123 });
+	a(err instanceof Error, true, "Instance of error");
+	a(err.constructor, Error, "Constructor");
+	a(err.name, "Error", "Name");
+	a(String(err), "Error: My Error", "String representation");
+	a(err.code, "MY_ERROR", "Code");
+	a(err.errno, 123, "Errno");
+	a(typeof err.stack, "string", "Stack trace");
+};