From c70cdfdaed69129c57a4c2e3301ff52ca51e17f2 Mon Sep 17 00:00:00 2001
From: Evdokim Kovach <ekovach@ohnosequences.com>
Date: Tue, 29 Dec 2015 14:39:54 +0100
Subject: [PATCH] an additional null check added

This additional check prevent invocation of `indexOf()` on possible null `ref` variable and improve therefore error messaging for malformed yaml files.

Before:
```
Cannot read property 'indexOf' of null
```

After:
```
Uncaught TypeError: Swagger 2.0 does not support null types
```
---
 lib/resolver.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/resolver.js b/lib/resolver.js
index deb688680..7095a907f 100644
--- a/lib/resolver.js
+++ b/lib/resolver.js
@@ -540,7 +540,7 @@ Resolver.prototype.resolveTo = function (root, property, resolutionTable, locati
   var sp, i;
   var ref = property.$ref;
   var lroot = root;
-  if (typeof ref !== 'undefined') {
+  if ((typeof ref !== 'undefined') && (ref !== null)) {
     if(ref.indexOf('#') >= 0) {
       var parts = ref.split('#');