Reverse Vowels of a String

export function reverseVowels(s: string): string {
  const vowelSet = new Set<string>('aeiou');
  const isVowel = (char: string) => vowelSet.has(char.toLowerCase());
 
  const arr = Array.from(s);
  const vowels = arr.filter(isVowel).reverse();
  let currentIndex = 0;
  let answer = '';
  for (const char of s) {
    if (isVowel(char)) {
      answer += vowels[currentIndex++];
    } else {
      answer += char;
    }
  }
  return answer;
}
 
/** Another ways: Two Pointer
function reverseVowels(s: string): string {
  const arr = Array.from(s);
  const set = new Set('aeiouAEIOU');
  const isVowel = (char: string) => set.has(char);
 
  let [start, end] = [0, arr.length - 1];
  while (start < end) {
    while (start < arr.length && !isVowel(arr[start])) {
      start += 1;
    }
    while (0 <= end && !isVowel(arr[end])) {
      end -= 1;
    }
    if (start < end) {
      [arr[start], arr[end]] = [arr[end], arr[start]];
      start += 1;
      end -= 1;
    }
  }
 
  return arr.join('');
}
*/