BLE & NFC Patterns

Quick Guide: Use react-native-ble-plx for BLE (scanning, connecting, GATT read/write/monitor). Use react-native-nfc-manager for NFC (NDEF read/write, tag technology access). BLE values are Base64-encoded -- decode before use. NFC operations follow request-technology/operate/cancel-technology lifecycle. Always clean up: remove BLE subscriptions, call cancelTechnologyRequest() for NFC, and destroy() the BleManager. MTU defaults to 23 bytes (20 usable) -- negotiate higher on Android. iOS auto-negotiates up to 187 bytes.

<critical_requirements>

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 call destroy() on BleManager when deallocating resources -- leaking the manager causes native memory leaks and zombie listeners)

(You MUST call discoverAllServicesAndCharacteristics() after connecting before any read/write/monitor operations -- GATT structure is not available until discovered)

(You MUST call cancelTechnologyRequest() in a finally block after every NFC operation -- failing to release the NFC session blocks subsequent scans)

(You MUST check BLE adapter state (PoweredOn) before scanning -- scanning while powered off or unauthorized throws errors silently on some devices)