<button class="btn btn-test">click me</button>
<p class="result"></p>

const btn = document.querySelector(`.btn`);
const result = document.querySelector(`.result`);

btn.addEventListener(`click`, (e) => {
	result.innerHTML  = `
		e.target.classList: ${e.target.classList} <br>
		e.target.classList.contains('btn'): ${e.target.classList.contains('btn')} <br>
		e.target.classList.contains('btn-active'): ${e.target.classList.contains('btn-active')}
	`;
})