State

data class AddEditNoteState(
   val title: String = "",
   val isNoteSaved: Boolean = false,
   val errorMsg: String? = null
)

ViewModel

class AddEditNoteViewModel @Inject constructor(
   savedStateHandle: SavedStateHandle,
   private val _addNoteUseCase: AddNoteUseCase,
   private val _getNoteById: GetNoteUseCase
): ViewModel() {

   // TODO may not need stateIn
   private val _addEditNoteSate = MutableStateFlow(AddEditNoteState())
   val addEditNoteState = _addEditNoteSate
      .asStateFlow()
      .stateIn(viewModelScope, WhileViewSubscribed, AddEditNoteState())

   fun onEvent(addEditNoteEvent: AddEditNoteEvent) {

		when(addEditNoteEvent) {
			is AddEditNoteEvent.SaveNote -> {
				viewModelScope.launch {
					try {
						_addNoteUseCase(
							Note(
								title = _addEditNoteSate.value.title,
							)
						)
						_addEditNoteSate.update { it.copy(isNoteSaved = true, errorMsg = null,) }

					} catch (e: NoteAppException.InvalidNoteException) {
						_addEditNoteSate.update { it.copy(isNoteSaved = false, errorMsg = e.msg) }
					}
				}
			}
		}
	}
}

In viewmodel if not saved success I want to navigate back but on error want to show snackbar. So for this should I create two LaunchEffect for navigate and snackbar or it is not good to have two LaunchEffect. In Compose Screen

val message = addEditNoteState.errorMsg
message?.let { msg ->
   LaunchedEffect(scaffoldState, msg) {
      scaffoldState.snackbarHostState.showSnackbar(message = msg)
   }
}

Currently I have handled only snackbar state like above. I want to follow Google recommended one-off ViewModel event.

the arch docs show an example of how to properly use state for displaying a snackbar https://developer.android.com/topic/architecture/ui-layer/events#compose_3