Sync actions

Your action is synchronous if the return type of its reduce() method is AppState?.

This means that the action will complete as soon as the reduce() method returns, and the state will be updated immediately. For example, here's a simple synchronous action that increments a counter by a given amount:

class Increment extends ReduxAction<AppState> {
  final int amount;
  Increment({this.amount});
  
  AppState? reduce() 
    => state.copy(counter: state.counter + amount));  
}

Note the reducer above has access to both the current state (state.counter) and to the action field (amount) that was passed when the action was dispatched.

// Current state
print(store.state.counter); // 2

// Dispatch a synchronous action
store.dispatch(Increment(amount: 3));

// The state was updated 
print(store.state.counter); // 5

Try running the: Increment Example.

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Next, let's learn more about asynchronous actions, which are necessary when you need to do something that takes time, like reading from a database or making a network request.