diff --git a/FileSaver.js b/FileSaver.js
index bf7a192..8a53d7d 100644
--- a/FileSaver.js
+++ b/FileSaver.js
@@ -235,7 +235,7 @@ var saveAs = saveAs
 // while `this` is nsIContentFrameMessageManager
 // with an attribute `content` that corresponds to the window
 
-if (typeof module !== "undefined" && module !== null) {
+if (typeof module !== "undefined" && module.exports) {
   module.exports = saveAs;
 } else if ((typeof define !== "undefined" && define !== null) && (define.amd != null)) {
   define([], function() {