module.exports.quicksort = function () {
  var sort = function (items) {
    if (items.length <= 1) return items
    var pivot = items.shift()
    var current
    var left = []
    var right = []

    while (items.length > 0) {
      current = items.shift()
      current < pivot ? left.push(current) : right.push(current)
    }
    return sort(left)
      .concat(pivot)
      .concat(sort(right))
  }

  return sort(Array.apply(this, arguments))
}