const { createStore, combineReducers } = require('redux')

const ActionType = {
  Inc: Symbol(),
  Dec: Symbol(),
  Pow: Symbol(),
}

const inc = () =>
  ({ type: ActionType.Inc })

const dec = () =>
  ({ type: ActionType.Dec })

const pow = n =>
  ({ type: ActionType.Pow, payload: n })


const counter = (state = 0, action) => {
  switch (action.type) {
    case ActionType.Inc:
      return state + 1

    case ActionType.Dec:
      return state - 1

    case ActionType.Pow:
      return state ** action.payload

    default:
      return state
  }
}

const reducer = combineReducers({ counter })

const store = createStore(reducer)

store.dispatch(inc())

store.dispatch(inc())

store.dispatch(inc())

store.dispatch(pow(3))



console.log(store.getState())