debounce.js

const debounce = (fn, wait, immediate) => {
  let timeout;
  return () => {
    const later = () => {
      timeout = null;
      if (!immediate) fn.apply(this)
    }
    const callNow = immediate && !timeout;
    clearTimeout(timeout)
    timeout = setTimeout(later, wait)
    if (callNow) fn.apply(this)
  }
}

const myDebounce = debounce(() => {
  console.log('call me')
}, 500)

const input = document.querySelector('input');
input.addEventListener('input', myDebounce)