kotlin-patterns

Kotlin null safety relies on non-nullable types by default, safe-call operators (?.), and the Elvis operator (?:) for defaults. Avoid force-unwrapping with !! and use require or check for preconditions with clear error messages.

Use coroutineScope with async and await to run tasks concurrently under structured concurrency. Use supervisorScope when child tasks can fail independently, and always call ensureActive before expensive work to respect cancellation.

Sealed classes suit restricted state hierarchies like Result types with Success, Failure, and Loading variants. Sealed interfaces work better for API error models where implementations need flexible inheritance while keeping when expressions exhaustive.

Flow is a cold reactive stream for asynchronous data with operators like debounce and mapLatest, integrated with coroutines. Sequence provides lazy synchronous evaluation for large collections with multiple chained operations.

GlobalScope launches coroutines outside any structured lifecycle, causing leaks and uncontrolled cancellation. Use coroutineScope or an injected application scope so child coroutines are cancelled when their parent completes or fails.

Yes, it includes build.gradle.kts configuration covering Kotlin JVM plugins, jvmToolchain settings, Ktor and Exposed dependencies, Kotest testing, and detekt static analysis setup.