import baseRandom from './baseRandom.js'

/**
 * A specialized version of `shuffle` which mutates and sets the size of `array`.
 *
 * @private
 * @param {Array} array The array to shuffle.
 * @param {number} [size=array.length] The size of `array`.
 * @returns {Array} Returns `array`.
 */
function shuffleSelf(array, size) {
  let index = -1
  const length = array.length
  const lastIndex = length - 1

  size = size === undefined ? length : size
  while (++index < size) {
    const rand = baseRandom(index, lastIndex)
    const value = array[rand]

    array[rand] = array[index]
    array[index] = value
  }
  array.length = size
  return array
}

export default shuffleSelf