From a8a08d8839dd8f0cf9a4a56d640ddd0af02d9295 Mon Sep 17 00:00:00 2001
From: Stewart Allen <stewart.allen@gmail.com>
Date: Mon, 8 Feb 2021 02:03:40 -0500
Subject: [PATCH] fix bug when layer has not output

---
 src/mode/fdm/prepare.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mode/fdm/prepare.js b/src/mode/fdm/prepare.js
index d0b8c971..f2200066 100644
--- a/src/mode/fdm/prepare.js
+++ b/src/mode/fdm/prepare.js
@@ -408,7 +408,7 @@
                 layerout.appendAll(tmpout);
                 lastOut = slice;
                 lastExt = lastOut.ext
-                if (layerRetract) {
+                if (layerRetract && layerout.length) {
                     layerout.last().retract = true;
                 }
             }