diff --git a/lib/fs.js b/lib/fs.js
index 8cd15eb04e..62712d57f8 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -185,12 +185,14 @@ function modeNum(m, def) {
 }
 
 fs.open = function(path, flags, mode, callback) {
-  var callback_ = arguments[arguments.length - 1];
-  var callback = (typeof(callback_) == 'function' ? callback_ : null);
+  callback = arguments[arguments.length - 1];
+  if (typeof(callback) !== 'function') {
+    callback = noop;
+  }
 
   mode = modeNum(mode, '0666');
 
-  binding.open(path, stringToFlags(flags), mode, callback || noop);
+  binding.open(path, stringToFlags(flags), mode, callback);
 };
 
 fs.openSync = function(path, flags, mode) {