es6-debounce.js

const debounce = (func, wait, immediate) => {
  let timeout

  return (...args) => {
    const later = () => {
      timeout = null
      if (!immediate) func(...args)
    }

    const callNow = immediate && !timeout

    clearTimeout(timeout)
    timeout = setTimeout(later, wait)

    if (callNow) func(...args)
  }
}