Should not blow up on modules that export primitives

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/getDefinePropertySrc.js b/lib/getDefinePropertySrc.js
index b856a7f..9ec4bde 100644
--- a/lib/getDefinePropertySrc.js
+++ b/lib/getDefinePropertySrc.js
@@ -11,9 +11,10 @@ var srcs = {
 };
 
 function getDefinePropertySrc() {
-    var src;
+    var src = "if (typeof(module.exports) === 'function' || \n" +
+            "(typeof(module.exports) === 'object' && module.exports !== null && Object.isExtensible(module.exports))) {\n";
 
-    src = Object.keys(srcs).reduce(function forEachSrc(preValue, value) {
+    src += Object.keys(srcs).reduce(function forEachSrc(preValue, value) {
         return preValue += "Object.defineProperty(module.exports, '" +
             value +
             "', {enumerable: false, value: " +
@@ -22,6 +23,8 @@ function getDefinePropertySrc() {
             "writable: true}); ";
     }, "");
 
+    src += "\n}";
+
     return src;
 }