From d2e9d8703758b553b541d6c159325a765057e7c2 Mon Sep 17 00:00:00 2001
From: Connor Turland <connorturland@gmail.com>
Date: Wed, 28 Jan 2015 21:04:00 -0500
Subject: [PATCH] when a topic was deleted, renderEdgeArrows was trying to call
 on a topic that was no longer existent to draw synapse direction, breaking
 the graph render

---
 app/assets/javascripts/src/Metamaps.JIT.js |  4 +++-
 app/assets/javascripts/src/Metamaps.js     | 11 +++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/app/assets/javascripts/src/Metamaps.JIT.js b/app/assets/javascripts/src/Metamaps.JIT.js
index 51240234..bef4ad59 100644
--- a/app/assets/javascripts/src/Metamaps.JIT.js
+++ b/app/assets/javascripts/src/Metamaps.JIT.js
@@ -1758,7 +1758,9 @@ Metamaps.JIT = {
         var posChild = adj.nodeTo.pos.getc(true);
 
         //plot arrow edge 
-        if (directionCat == "none") {
+        if (!direction) {
+            // render nothing for this arrow if the direction couldn't be retrieved
+        } else if (directionCat == "none") {
             edgeHelper.line.render({
                 x: pos.x,
                 y: pos.y
diff --git a/app/assets/javascripts/src/Metamaps.js b/app/assets/javascripts/src/Metamaps.js
index 95a76745..44df0d4c 100644
--- a/app/assets/javascripts/src/Metamaps.js
+++ b/app/assets/javascripts/src/Metamaps.js
@@ -356,10 +356,13 @@ Metamaps.Backbone.init = function () {
             return Metamaps.Topics.get(this.get('node2_id'));
         },
         getDirection: function () {
-            return [
-                    this.getTopic1().get('node').id,
-                    this.getTopic2().get('node').id
-                ];
+            var t1 = this.getTopic1(),
+                t2 = this.getTopic2();
+
+            return t1 && t2 ? [
+                    t1.get('node').id,
+                    t2.get('node').id
+                ] : false;
         },
         getMapping: function () {