UseReducer<T> constructor

UseReducer<T>(Reducer<T> reducer, T initialState)

A ReactterHook that manages state using reducer method.

UseReducer accepts a reducer method and returns the current state paired with a dispatch method. (If you’re familiar with Redux, you already know how this works.)

Contains a value of type T which represents the current state.

When value is different to previous state, UseReducer execute update to notify to container instance that has changed and in turn executes onWillUpdate and onDidUpdate.

Example:

class Store {
  final int count;

  Store({this.count = 0});
}

 Store _reducer(Store state, ReactterAction<String, int?> action) {
   switch (action.type) {
     case 'increment':
       return Store(count: state.count + (action.payload ?? 1));
     case 'decrement':
       return Store(count: state.count + (action.payload ?? 1));
     default:
       throw UnimplementedError();
   }
 }

class AppController {
  late final state = UseReducer(_reducer, Store(count: 0));

  AppController() {
    print("count: ${state.value.count}"); // count: 0;
    state.dispatch(ReactterAction(type: 'increment', payload: 2));
    print("count: ${state.value.count}"); // count: 2;
    state.dispatch(ReactterAction(type: 'decrement'));
    print("count: ${state.value.count}"); // count: 1;
  }
}

Implementation

UseReducer(
  this.reducer,
  T initialState,
) : _state = UseState<T>(initialState) {
  UseEffect(update, [_state]);
}