Permutations in JavaScript?

Question

I\'m trying to write a function that does the following:

• takes an array of integers as an argument (e.g. [1,2,3,4])
• creates an array of all the possib

Answer 1

I had a crack at making a version of this that attempts to be concise yet readable, and purely functional programming.

function stringPermutations ([...input]) {
  if (input.length === 1) return input;

  return input
    .map((thisChar, index) => {
      const remainingChars = [...input.slice(0, index), ...input.slice(index + 1)];
      return stringPermutations(remainingChars)
        .map(remainder => thisChar + remainder);
    })
    .reduce((acc, cur) => [...acc, ...cur]);
}

Note that the argument formatting turns an input string into an array. Not sure if that's a bit too magical.. Not sure I've seen it in the wild. For real readability I'd probably instead do input = [...input] for the first line of the function.