
/**
 * Returns a function, that, as long as it continues to be invoked, will not 
 * be triggered. The function will be called after it stops being called for
 * N milliseconds. If `immediate` is passed, trigger the function on the
 * leading edge, instead of the trailing.
 * 
 * @see https://davidwalsh.name/javascript-debounce-function
 */
export function debounce(func: (...args: any[]) => void, wait: number, immediate: boolean = false) {
  let timeout = null
  return function () {
    const context = this, args = arguments
    const later = function () {
      timeout = null
      if (!immediate) func.apply(context, args)
    }
    const callNow = immediate && !timeout
    clearTimeout(timeout)
    timeout = setTimeout(later, wait)
    if (callNow) func.apply(context, args)
  }
}