add method

System<State, Event> add({ Reduce<State, Event>? reduce, Effect<State, Event>? effect, })

Adds reduce or effect into the system.

If we adds reduce or effect multiple times, the call side order is in serial.

Usage Example

Below code showed how adds reduce or effect into system:

counterSystem
  ...
  .add(reduce: (state, event) {
    if (event is Increment) return state + 1;
    return state;
  })
  .add(reduce: (state, event) {
    if (event is Decrement) return state - 1;
    return state;
  })
  .add(effect: (state, oldState, event, dispatch) {
    // effect - log update
    print('\nEvent: $event');
    print('OldState: $oldState');
    print('State: $state');
  })
  ...

Implementation

System<State, Event> add({
  Reduce<State, Event>? reduce,
  Effect<State, Event>? effect,
}) => withContext<void>(
  createContext: () {},
  reduce: reduce,
  effect: effect == null ? null : (context, state, oldState, event, dispatch) {
    effect(state, oldState, event, dispatch);
  }
);