permutation.js

permutation.js

const createPermutation = (arr, selected = new Set(), output = []) => {
  if (selected.size >= arr.length) {
    output.push([...selected].map((i) => arr[i]));
    return output;
  }
  for (let i = 0; i < arr.length; i++) {
    if (selected.has(i)) {
      continue;
    }
    selected.add(i);
    createPermutation(arr, selected, output);
    selected.delete(i);
  }
  return output;
};

const result = createPermutation([1, 2, 3]);
console.log(result);

/*
[
  [ 1, 2, 3 ],
  [ 1, 3, 2 ],
  [ 2, 1, 3 ],
  [ 2, 3, 1 ],
  [ 3, 1, 2 ],
  [ 3, 2, 1 ]
]
*/