clarify and defend against null tags from onesignal

Author: hawkrives

flow-typed/npm/react-native-onesignal_vx.x.x.js

@@ -110,7 +110,7 @@ declare module 'react-native-onesignal' {
 
     static sendTag(key: string, value: string): void;
     static sendTags(TagsObject): void;
-    static getTags((TagsObject | Error) => mixed): void;
+    static getTags((null | TagsObject | Error) => mixed): void;
     static deleteTag(key: string): void;
 
     static enableVibrate(enable: boolean): void;

source/redux/parts/notifications.js

@@ -14,7 +14,7 @@ import OneSignal, {
 } from 'react-native-onesignal'
 import pify from 'pify'
 
-const getOneSignalTags: () => Promise<TagsObject> = pify(OneSignal.getTags, {
+const getOneSignalTags: () => Promise<?TagsObject> = pify(OneSignal.getTags, {
 	errorFirst: false,
 })
 const getOneSignalPermissions: () => Promise<SubscriptionState> = pify(
@@ -100,7 +100,10 @@ export function hydrate(): ThunkAction<HydrateChannelsAction> {
 			getOneSignalTags(),
 			getOneSignalPermissions(),
 		])
-		let channels = new Set(Object.keys(tags))
+		let channels = new Set()
+		if (tags) {
+			channels = new Set(Object.keys(tags))
+		}
 		dispatch({type: CHANNELS_HYDRATE, payload: {channels, permissions}})
 	}
 }