Shuffle.js

function shuffle (array) {
  let remaining = array.length

  // While there remain elements to shuffle.
  while (remaining) {
    // Pick a remaining index.
    let index = Math.floor(Math.random() * remaining--)
    // And swap it with the current element.
    let item = array[remaining]

    array[remaining] = array[index]
    array[index] = item
  }

  return array
}

Better? Worse? IDK, definitely messier.

function swap(array, a, b, item = array[b]) {
  array[b] = array[a]
  array[a] = item
}

function shuffle (array, remaining = array.length) {
  while (remaining)
    swap(array, Math.floor(Math.random() * remaining--), remaining)
  return array
}