6to5/polyfill can now only be required **once**

2015-01-23 00:19:30 +11:00
parent 51b6946a98
commit 377212290f
1 changed files with 5 additions and 0 deletions
--- a/lib/6to5/polyfill.js
+++ b/lib/6to5/polyfill.js
@@ -1,4 +1,9 @@
 "use strict";

+if (global._6to5Polyfill) {
+  throw new Error("only one instance of 6to5/polyfill is allowed");
+}
+global._6to5Polyfill = true;
+
 require("core-js/shim");
 require("regenerator-6to5/runtime");