rollSantas.js

rollSantas.js

const shuffle = input => {
  const array = [...input]
  for (let i = array.length - 1; i >= 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [array[i], array[j]] = [array[j], array[i]];
  }
  return array
}

const slide1 = ([first, ...rest]) => ([...rest, first])
const zip = (listA, listB) => listA.map((a, i) => [a, listB[i]])

const rollSantas = names => {
  const shuffledNames = shuffle(names)
  return zip(shuffledNames, slide1(shuffledNames))
}

const testInput = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
console.log(rollSantas(testInput))