From b0eb68130618bbdf6358c135d7c393e46fe1756d Mon Sep 17 00:00:00 2001
From: Kyle Fang <zhigang1992@gmail.com>
Date: Thu, 13 Aug 2020 12:37:05 +0800
Subject: [PATCH] fix: add observer compatibility to auth APIs

---
 packages/auth/lib/index.d.ts |  8 +++++---
 packages/auth/lib/index.js   | 15 ++++++++++++---
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/packages/auth/lib/index.d.ts b/packages/auth/lib/index.d.ts
index 4eb53171..20673d73 100644
--- a/packages/auth/lib/index.d.ts
+++ b/packages/auth/lib/index.d.ts
@@ -1254,7 +1254,7 @@ export namespace FirebaseAuthTypes {
      *
      * @param listener A listener function which triggers when auth state changed (for example signing out).
      */
-    onAuthStateChanged(listener: AuthListenerCallback): () => void;
+    onAuthStateChanged(listener: CallbackOrObserver<AuthListenerCallback>): () => void;
 
     /**
      * Listen for changes in ID token.
@@ -1276,7 +1276,7 @@ export namespace FirebaseAuthTypes {
      *
      * @param listener A listener function which triggers when the users ID token changes.
      */
-    onIdTokenChanged(listener: AuthListenerCallback): () => void;
+    onIdTokenChanged(listener: CallbackOrObserver<AuthListenerCallback>): () => void;
 
     /**
      * Adds a listener to observe changes to the User object. This is a superset of everything from
@@ -1302,7 +1302,7 @@ export namespace FirebaseAuthTypes {
      * @react-native-firebase
      * @param listener A listener function which triggers when the users data changes.
      */
-    onUserChanged(listener: AuthListenerCallback): () => void;
+    onUserChanged(listener: CallbackOrObserver<AuthListenerCallback>): () => void;
 
     /**
      * Signs the user out.
@@ -1634,6 +1634,8 @@ export namespace FirebaseAuthTypes {
   }
 }
 
+type CallbackOrObserver<T extends (...args: any[]) => any> = T | { next: T };
+
 declare module '@react-native-firebase/auth' {
   // tslint:disable-next-line:no-duplicate-imports required otherwise doesn't work
   import { ReactNativeFirebase } from '@react-native-firebase/app';
diff --git a/packages/auth/lib/index.js b/packages/auth/lib/index.js
index 24110ce9..d020699d 100644
--- a/packages/auth/lib/index.js
+++ b/packages/auth/lib/index.js
@@ -129,7 +129,14 @@ class FirebaseAuthModule extends FirebaseModule {
     };
   }
 
-  onAuthStateChanged(listener) {
+  _parseListener(listenerOrObserver) {
+    return typeof listenerOrObserver === 'object'
+      ? listenerOrObserver.next.bind(listenerOrObserver)
+      : listenerOrObserver;
+  }
+
+  onAuthStateChanged(listenerOrObserver) {
+    const listener = this._parseListener(listenerOrObserver);
     const subscription = this.emitter.addListener(
       this.eventNameForApp('onAuthStateChanged'),
       listener,
@@ -143,7 +150,8 @@ class FirebaseAuthModule extends FirebaseModule {
     return () => subscription.remove();
   }
 
-  onIdTokenChanged(listener) {
+  onIdTokenChanged(listenerOrObserver) {
+    const listener = this._parseListener(listenerOrObserver);
     const subscription = this.emitter.addListener(
       this.eventNameForApp('onIdTokenChanged'),
       listener,
@@ -157,7 +165,8 @@ class FirebaseAuthModule extends FirebaseModule {
     return () => subscription.remove();
   }
 
-  onUserChanged(listener) {
+  onUserChanged(listenerOrObserver) {
+    const listener = this._parseListener(listenerOrObserver);
     const subscription = this.emitter.addListener(this.eventNameForApp('onUserChanged'), listener);
     if (this._authResult) {
       Promise.resolve().then(() => {