diff --git a/web/_js/draw.js b/web/_js/draw.js
index 7d69c8d6..29fd815b 100644
--- a/web/_js/draw.js
+++ b/web/_js/draw.js
@@ -374,6 +374,8 @@ function initDraw() {
 
 	function render(path) {
 
+		if (!Array.isArray(path)) return
+
 		context.globalCompositeOperation = "source-over";
 		context.clearRect(0, 0, canvas.width, canvas.height);