From 0456896d71ccbc6b0ef2b1332a93a23ae6b45178 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gina=20H=C3=A4u=C3=9Fge?= <gina@octoprint.org>
Date: Mon, 24 Jul 2017 12:52:13 +0200
Subject: [PATCH] GCODE Viewer: Fix issue with lookup of layer index 0

We were just testing if z_heights[z] was truthy. If the layer index was
set but 0 that wasn't properly detected and let to overwriting our
layer information. Instead check explicitly against undefined.

Closes #2017
---
 src/octoprint/static/gcodeviewer/js/Worker.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/octoprint/static/gcodeviewer/js/Worker.js b/src/octoprint/static/gcodeviewer/js/Worker.js
index 15658392..f96fa706 100644
--- a/src/octoprint/static/gcodeviewer/js/Worker.js
+++ b/src/octoprint/static/gcodeviewer/js/Worker.js
@@ -545,7 +545,7 @@ var doParse = function () {
         }
 
         if (typeof(z) !== 'undefined' && z !== prevZ) {
-            if (z_heights[z]) {
+            if (z_heights[z] !== undefined) {
                 layer = z_heights[z];
             } else {
                 layer = model.length;