/**
 * Return an array with the numbers from 0 to n-1, in a random order
 */
const getRandomArray = n => {
  if (n === 0) return []
  if (n === 1) return [0]

  const res = getRandomArray(n - 1)
  const next = Math.floor(Math.random() * n)
  res.splice(next, 0, n - 1) // Add n-1 at a random position in the array

  return res
}

module.exports.getRandomArray = getRandomArray

/*
 * Default compareKeys function will work for numbers, strings and dates
 */
const defaultCompareKeysFunction = (a, b) => {
  if (a < b) return -1
  if (a > b) return 1
  if (a === b) return 0

  const err = new Error("Couldn't compare elements")
  err.a = a
  err.b = b
  throw err
}

module.exports.defaultCompareKeysFunction = defaultCompareKeysFunction

/**
 * Check whether two values are equal (used in non-unique deletion)
 */
const defaultCheckValueEquality = (a, b) => a === b

module.exports.defaultCheckValueEquality = defaultCheckValueEquality