compose-multiplatform-patterns

Use a single immutable data class for screen state exposed as StateFlow from the ViewModel, and collect it in Compose with collectAsStateWithLifecycle. Update state via MutableStateFlow.update inside viewModelScope coroutines.

Define routes as @Serializable objects or data classes and register them with composable<Route> in a NavHost using Compose Navigation 2.8+. Retrieve arguments with backStackEntry.toRoute<Route>() and navigate by passing route instances.

Yes, use expect/actual declarations for platform composables, such as an expect PlatformStatusBar in commonMain with actual implementations in androidMain and iosMain. Android can use system UI controller libraries while iOS relies on UIKit interop or Info.plist.

Frequent recomposition usually comes from unstable parameter types, new object instances created in composable parameters, or unkeyed lazy list items. Mark models @Immutable, remember computed values, and provide stable keys in LazyColumn items.

Use a sealed-interface event sink when a screen has many user actions, so the composable takes a single onEvent lambda instead of numerous callbacks. The ViewModel handles events in a when block, keeping the composable stateless and testable.