const doc = {
    app: document.querySelector("#app"),
    button: document.createElement("button")
};

let state = { 
    count: 0 
};

window.addEventListener('load', () => {
    init();
})

function init() {    
    render();
    doc.button.addEventListener("click", () =>
      updateState()
    );
    doc.app.appendChild(doc.button);
}

function updateState() {
    state.count += 1
    render();
}

function render() {
    doc.button.innerText = `Count: ${state.count}`;
}