Abstract Subscribable Controller with reducer

AbstractSubscribableController.ts

type Fn = (...args: any[]) => any;
type Reducer = Record<string, Fn>;
type Unsubscribe = () => void;

let seed = 0;
export abstract class AbstractSubscribableController<TReducer extends Reducer> {
  protected observers: Map<number, TReducer> = new Map();

  subscribe(reducer: TReducer): Unsubscribe {
    seed++;
    this.observers.set(seed, reducer);

    // Retornando o unsubscribe
    return () => {
      this.observers.delete(seed);
    };
  }

  // Aqui pode ter o nome que quiser: dispatch, emit, notify, etc
  dispatch<K extends keyof TReducer>(event: K, ...args: Parameters<TReducer[K]>) {
    this.observers.forEach((observer) => observer[event]?.(...args));
  }
}

TestControllerImpl.ts

class TestControllerImpl extends AbstractSubscribableController<TestReducer> implements TestController {
  constructor() {
    super();
  }

  public method1() {
    try {
      this.dispatch('onLoad');

      // ...

      this.dispatch('onSuccess', {
        items: ['olá', 'mundo'],
        flag: false
      });
    } catch (error) {
      if (error instanceof Error) {
        this.dispatch('onError', error.message);
      }
    }
  }

  public method2() {
    // Se vc definir um reducer com mais de parâmetro é assim que seta os valores
    this.dispatch('onTest', true, 'teste');
  }
}

TestReducer.ts

type SuccessState = {
  items: string[];
  flag: boolean;
}

export type TestReducer = {
  onSuccess: (state: SuccessState) => void;
  onError: (message: string) => void;
  onLoad: () => void;
  onTest: (loading: boolean, message: string) => void;
}