First react counter example without react

gistfile1.txt

function counter(state, action) {
  if (typeof state === 'undefined') {
    return 0;
  }
  
  if (action.type === 'INCREMENT') {
    return state + 1;
  } else if (action.type === 'DECREMENT'){
    return state  -1;
  }else {
    return state;
  }
}

var createStore = Redux.createStore;
var store = createStore(counter);

console.log(store.getState());

store.dispatch({ type: 'INCREMENT' });
console.log(store.getState());

var render = function(){
  document.body.innerText = store.getState();
};

store.subscribe(render);
render();

document.addEventListener('click', function(){
  store.dispatch({type: 'INCREMENT'});
});