Less imagining.
More experimenting.

import { createStore } from '@tagna/udiot/browser';

const store = createStore(
  { count: input.initial },
  (state, action) => ({
    count: state.count + action.payload
  })
);

for (const step of input.steps) {
  await store.dispatch({ type: 'ADD', payload: step });
}
if (input.undo) store.undo();

store.getState();
store.getHistory();