Changing state is optional

For both sync and async reducers, returning a new state is always optional. If you don't plan on changing the state, simply return null. This is the same as returning the state unchanged:

class GetAmount extends ReduxAction<AppState> {
  
  Future<AppState?> reduce() async {    
    int amount = await getAmount();
    
    if (amount == 0) 
      return null;
    else 
      return state.copy(counter: state.counter + amount));
  }
}

This is also useful when you want an action that simply starts other async processes or dispatches other actions. For example:

class InitAction extends ReduxAction<AppState> {
  
  AppState? reduce() {
    dispatch(ReadDatabaseAction());        
    dispatch(StartTimersAction());          
    dispatch(TurnOnListenersAction());              
    return null;          
  }
}

Note the reduce() method has direct access to dispatch.

---

Next, let's see how to reduce boilerplate by defining our own base action class.