My take on the `debounce` function

debounce.js

/**
 * Debounce
 * This will create a function that can be called multiple times and only be
 * executed once, within a threshold you speficy
 * @param {function} callback Callback function to be executed
 * @param {number} threshold Time to wait before executing the callback
 * @return {function} The function that can be triggered multiple time
 */
function debounce(callback, threshold = 1000) {
  // input validation
  if (!callback || typeof callback !== 'function') {
    return () => {}
  }
  // save previous timeout id on this closure (the magic)
  let timeoutId = null
  // end function
  return () => {
    // clear previous timeout
    clearTimeout(timeoutId)
    // create/execute new timeout
    timeoutId = setTimeout(() => {
      callback()
    }, threshold)
  }
}