function debounce (func, wait, immediate) {
  let timeout
  return function () {
    const context = this; const args = arguments
    const callNow = immediate && !timeout
    clearTimeout(timeout)
    timeout = setTimeout(() => {
      timeout = null
      if (!immediate) func.apply(context, args)
    }, wait)
    if (callNow) func.apply(context, args)
  }
}

module.exports = { debounce }