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