Reformat The String

export function reformat(s: string): string {
  const alphabets: string[] = [];
  const digits: string[] = [];
  for (const char of s) {
    if (/[a-z]/.test(char)) {
      alphabets.push(char);
    } else {
      digits.push(char);
    }
  }
 
  const [m, n] = [alphabets.length, digits.length];
  if (1 < Math.abs(m - n)) {
    return '';
  }
 
  let answer = '';
  let isAlphabet = m >= n;
  for (let i = 0; i < m + n; i++) {
    const index = Math.floor(i / 2);
    if (isAlphabet) {
      answer += alphabets[index];
    } else {
      answer += digits[index];
    }
    isAlphabet = !isAlphabet;
  }
  return answer;
}