Randomly align items between a range of numbers, no duplicates.

randomRange.js

const random = require('lodash/random')

const swap = (arr, a, b) => {
  const c = arr[a]
  arr[a] = arr[b]
  arr[b] = c
}

/**
 * Generate random number between a range, no duplicate items,
 * algorithm referenced from:
 * https://en.wikipedia.org/wiki/Fisher%E2%80%93Yates_shuffle
 * @param {Number} lower lower number
 * @param {Number} upper upper number
 */
const rangeRandom = (lower, upper) => {
  const scrach = []

  for (let i = lower; i <= upper; i++) {
    scrach.push(i)
  }

  const size = scrach.length

  for (let i = 0; i < size - 2; i++) {
    const j = random(i, size - 1)

    swap(scrach, i, j)
  }

  return scrach
}

console.log(rangeRandom(1, 12))