<button>Open drawer</button>

<div class="drawer">
  <div>
    <h2>I'm a drawer</h2>
    <p>Lorem ipsum dolor sit amet consectetur adipisicing.</p>
  </div>
</div>

const drawer = document.querySelector(".drawer");
const button = document.querySelector("button");

button.addEventListener("click", () => {
  drawer.classList.toggle("open");
});