From 6f4d67d1a5f31969cb59a57a999014ea617f9651 Mon Sep 17 00:00:00 2001
From: Jeremy Penner <jeremy@sporktania.com>
Date: Mon, 25 Dec 2023 21:47:39 -0500
Subject: [PATCH] Fix exception attempting to create text-only animation

---
 index.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index cee260d..1d985ab 100644
--- a/index.js
+++ b/index.js
@@ -496,7 +496,10 @@ const linkDetail = (element, filename) => {
 const createAnimation = (prop, animation) => {
     const frames = []
     for (let istate = animation.startState; istate <= animation.endState; istate ++) {
-        frames.push(compositeCels(celsFromMask(prop, prop.celmasks[istate])))
+        const frame = compositeCels(celsFromMask(prop, prop.celmasks[istate]))
+        if (frame != null) {
+            frames.push(frame)
+        }
     }
     if (frames.length == 1) {
         return imageFromCanvas(frames[0].canvas)