Counter Example With Redux

counter-redux.js

let reducer = function(state = 0, action) {
    switch(action.type) {
        case 'INCREMENT':
            return state + 1;
        case 'DECEMENT':
            return state - 1;
        default:
            return state;
    }
};

const store = Redux.createStore(reducer);

let render = count => document.getElementById('count').innerHTML = count;

store.subscribe(() => {
    render(store.getState());
});

store.dispatch({ type: '' });

document.getElementById('increment')
    .addEventListener('click', () => {
        store.dispatch({ type: 'INCREMENT' });
    });

document.getElementById('decerement')
    .addEventListener('click', () => {
        store.dispatch({ type: 'DECEMENT' });
    });