Push Notification Patterns

Quick Guide: Two main approaches: expo-notifications (Expo workflow, unified API for push + local) and @react-native-firebase/messaging (bare RN, FCM/APNs direct). Always request permissions before retrieving tokens. Handle three notification states: foreground (app open), background (app minimized), and quit (app killed). Set up Android notification channels before displaying any notification. Push notifications require a physical device -- they do not work on emulators or simulators.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST request notification permissions BEFORE retrieving push tokens -- calling getExpoPushTokenAsync or messaging().getToken() without permission will fail or return an unusable token)

(You MUST create an Android notification channel BEFORE displaying any notification on Android 8+ -- notifications without a channel are silently dropped)

(You MUST handle ALL three notification states: foreground (onMessage/addNotificationReceivedListener), background (setBackgroundMessageHandler/registerTaskAsync), and tap/response (addNotificationResponseReceivedListener/onNotificationOpenedApp + getInitialNotification))

(You MUST clean up notification listeners on unmount -- leaked listeners cause memory leaks and duplicate handlers)