recreating-redux-4.js

export function createStore(reducer, initialState) {
  let listeners = [];
  let currentState = initialState;

  function getState() {
    return currentState;
  }

  function subscribe(listener) {
    listeners.push(listener);
  }

  function dispatch(action) {
    currentState = reducer(currentState, action);

    listeners.forEach(listener => listener());
  }

  dispatch({ type: 'INIT' });

  return { getState, subscribe, dispatch };
}