So siehts ganz gut aus !

node_modules/es5-ext/object/ensure-promise.js

@@ -0,0 +1,9 @@
+"use strict";
+
+var safeToString = require("../safe-to-string")
+  , isPromise    = require("./is-promise");
+
+module.exports = function (value) {
+	if (!isPromise(value)) throw new TypeError(safeToString(value) + " is not a promise");
+	return value;
+};