debounced-promise.js

function debounce(fn, interval) {
  let timeout;
  
  return function(...args) {
    clearTimeout(timeout);
    return new Promise(resolve => {
      timeout = setTimeout(() => resolve(fn(...args)), interval);
    });
  }
}

const debounced = debounce(() => console.log("hello"), 200);

window.addEventListener('keydown', () => {
  debounced().then(() => console.log("well hello to you too!"));
});