swift

Model each state as its own type instead of one struct with many optionals. Use a protocol with conforming structs like ScannedText and ScannedBarcode, or an enum with associated values, so fields like barcode and barcodeType are nonoptional on the variant where they are valid.

Choose one concurrency model per feature. Use Swift async/await, Task, and actors when the whole operation fits Swift concurrency; use a private serial DispatchQueue when Apple delegate APIs, C++ bridges, JS runtimes, or Nitro thread boundaries already revolve around queues.

No. Properties should only expose cheap, immediately readable state. If a value requires a thread hop, session query, or fallible native operation, expose an async getter method or, in Nitro Modules, a Promise<T> method using Promise.parallel(queue).

Synchronous queue hops block the calling thread and can deadlock, especially in property getters and setters. Replace them with DispatchQueue.async, an async API boundary, or a Nitro Promise method so callers explicitly wait for queue-bound work.

Keep one top-level type per file and never put extensions inside Hybrid* implementation files. Place conversions in named Type+operation.swift files, keep Hybrid*Factory.swift as orchestration only, and extract permission checks and platform glue into focused helper files.

Treat locks as a last resort after ruling out MainActor, serial queues, or immutable snapshots. If a lock is needed for a listener registry, mutate and snapshot under the lock, then unlock before invoking callbacks or calling into JS or Nitro.