From fc14fe3b64dae6a1663b9cf838661e843efd6199 Mon Sep 17 00:00:00 2001
From: Alexander Ott <alexander.ott.at@gmail.com>
Date: Fri, 13 May 2016 16:37:39 +0200
Subject: [PATCH] Do not parse relation if it is 'null'

---
 backbone-nested-models.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/backbone-nested-models.js b/backbone-nested-models.js
index 45f0be2..2c5a8ce 100644
--- a/backbone-nested-models.js
+++ b/backbone-nested-models.js
@@ -150,7 +150,9 @@
 
       _.each(this.relations, function(rel, key) {
         if (_.has(attrs, key)) {
-          attrs[key] = attrs[key].toJSON();
+          if(attrs[key] !== null) {
+            attrs[key] = attrs[key].toJSON();
+          }
         } else {
             attrs[key] = (new rel()).toJSON();
         }