From 37ed0d2b5e01e4539388b379c5646beb5e3d66ff Mon Sep 17 00:00:00 2001
From: Tim Blakely <tim.blakely@gmail.com>
Date: Tue, 23 Jan 2018 09:37:17 -0800
Subject: [PATCH] fix(afs/typings): valueChanges should return
 Observable<T|null> (#1321)

---
 src/firestore/document/document.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/firestore/document/document.ts b/src/firestore/document/document.ts
index cad381027..8af9956b5 100644
--- a/src/firestore/document/document.ts
+++ b/src/firestore/document/document.ts
@@ -89,9 +89,9 @@ export class AngularFirestoreDocument<T> {
   /**
    * Listen to unwrapped snapshot updates from the document.
    */
-  valueChanges(): Observable<T> {
+  valueChanges(): Observable<T|null> {
     return this.snapshotChanges().map(action => {
-      return (action.payload.exists ? action.payload.data() : null) as T;
+      return action.payload.exists ? action.payload.data() as T : null;
     });
   }
 }