kotlin-coroutines-flows

Use coroutineScope with multiple async blocks to run suspending work concurrently, then call await on each Deferred. This keeps the work structured so a failure cancels siblings and the parent waits for all children.

Call stateIn on the Flow with viewModelScope, SharingStarted.WhileSubscribed(5000), and an initial value. WhileSubscribed keeps the upstream active for five seconds after the last subscriber leaves, surviving configuration changes.

Use StateFlow for UI state that always has a current value and should be replayed to new collectors. Use SharedFlow for one-time events like snackbars or navigation that should not be re-delivered after rotation.

Dispatchers.IO is only available on JVM and Android. In KMP common code, use Dispatchers.Default or Dispatchers.Main, which exist on all platforms, or inject the IO dispatcher through dependency injection per platform.

Use runTest with the Turbine library: call state.test and assert each awaitItem in sequence. Combine with advanceUntilIdle and a TestDispatcher to control virtual time, and fake repositories backed by MutableStateFlow.

GlobalScope launches coroutines with no parent, so they leak beyond the lifecycle that started them and cannot be cancelled structurally. Use viewModelScope, lifecycleScope, or a child coroutineScope instead.