diff --git a/lights.js b/lights.js
index 0d5a7c6..8cbaa9b 100644
--- a/lights.js
+++ b/lights.js
@@ -99,7 +99,7 @@ function tick_pattern() {
 
   let parsed = pattern.parsed;
 
-  if (parsed.length > 0) {
+  if (parsed && parsed.length > 0) {
     for (let i = 0; i < cfg.leds; i++) {
       for (let id in parsed) {
         let command = parsed[id];