From 1691ece378e8ec6a7379edc608a286b56ff3cd81 Mon Sep 17 00:00:00 2001
From: Piotr Gajowniczek <piotrgajow@gmail.com>
Date: Sun, 29 Jan 2017 12:46:38 +0100
Subject: [PATCH] Add check for undefined value for sorting mechanism

Sorting wont throw exception during sorting, when branch does not have
value for given field
---
 src/tree-grid-directive.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tree-grid-directive.js b/src/tree-grid-directive.js
index 08d514b..d3da0f8 100644
--- a/src/tree-grid-directive.js
+++ b/src/tree-grid-directive.js
@@ -252,7 +252,7 @@
                             }
 
                             var key = function (x) {
-                                return (x[col.field] === null ? "" : x[col.field].toLowerCase());
+                                return ((x[col.field] === null || x[col.field] === undefined) ? "" : x[col.field].toLowerCase());
                             };
 
                             switch (col.sortingType) {