diff --git a/webcomponents.js b/webcomponents.js
index 2d090df..8112c73 100644
--- a/webcomponents.js
+++ b/webcomponents.js
@@ -34,7 +34,7 @@
       }
     }
     // log flags
-    if (flags.log) {
+    if (flags.log && flags.log.split) {
       var parts = flags.log.split(',');
       flags.log = {};
       parts.forEach(function(f) {