diff --git a/bin/uglifyjs b/bin/uglifyjs
index 9b335b74..57370e6a 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -470,7 +470,7 @@ function normalize(o) {
 
 function getOptions(x, constants) {
     x = ARGS[x];
-    if (x == null) return null;
+    if (!x) return null;
     var ret = {};
     if (x !== "") {
         var ast;