export interface StateMachineTransitionResult<State, Effect> {  state: State;  effects: Effect[];} export type StateMachineTransition<State, Event, Context, Effect> = (  state: State,  context: Context,  event: Event) => StateMachineTransitionResult<State, Effect>; export interface StateMachineContainer<State, Event, Context, Effect> {  readonly state: State;  dispatch(event: Event, context: Context): StateMachineTransitionResult<State, Effect>;  setState(nextState: State): void;  reset(): void;} interface CreateStateMachineOptions<State, Event, Context, Effect> {  initialState: State;  transition: StateMachineTransition<State, Event, Context, Effect>;} /** * * @param options */export function createStateMachine<State, Event, Context, Effect>(  options: CreateStateMachineOptions<State, Event, Context, Effect>): StateMachineContainer<State, Event, Context, Effect> {  let currentState = options.initialState;   return {    get state(): State {      return currentState;    },    dispatch(event: Event, context: Context): StateMachineTransitionResult<State, Effect> {      const transition = options.transition(currentState, context, event);      currentState = transition.state;      return transition;    },    setState(nextState: State): void {      currentState = nextState;    },    reset(): void {      currentState = options.initialState;    },  };}