Fix: polyfill should not override native Promise

Author: linuxwolf

lib/algorithms/helpers.js

@@ -6,7 +6,9 @@
  */
 "use strict";
 
-require("es6-promise").polyfill();
+if (typeof Promise === "undefined") {
+  require("es6-promise").polyfill();
+}
 
 // ###
 exports.int32ToBuffer = function(v, b) {