From c3d44d6c745fce0779aaab2bdc7c36c6a1aeebe1 Mon Sep 17 00:00:00 2001
From: Chris Bianca <me@chrisbianca.com>
Date: Fri, 13 Oct 2017 09:05:57 +0100
Subject: [PATCH] [firestore] Correctly handle `undefined` values

---
 lib/modules/firestore/utils/serialize.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/modules/firestore/utils/serialize.js b/lib/modules/firestore/utils/serialize.js
index 6015848b..3ef0b09a 100644
--- a/lib/modules/firestore/utils/serialize.js
+++ b/lib/modules/firestore/utils/serialize.js
@@ -40,7 +40,7 @@ const buildNativeArray = (array: Object[]): any[] => {
 const buildTypeMap = (value: any): any => {
   const typeMap = {};
   const type = typeOf(value);
-  if (value === null) {
+  if (value === null || value === undefined) {
     typeMap.type = 'null';
     typeMap.value = null;
   } else if (value === DELETE_FIELD_VALUE) {