1: A , 26: Z, 27: AA

alphabet-counter.js

function alphabetCounter(counter) {
  counter = Math.abs(counter)
  counter = !counter ? 1 : counter
  let remainder = counter % 26
  let quotient = Math.floor(counter / 26)
  let result = remainder ? String.fromCharCode(64 + remainder) : (--quotient, 'Z');
  return quotient ? alphabetCounter(quotient) + result : result;
}