Angular: UID function creator

nextUid

var uid = ['0', '0', '0'];

function nextUid() {
  var index = uid.length;
  var digit;

  while(index) {
    index--;
    digit = uid[index].charCodeAt(0);
    if (digit == 57 /*'9'*/) {
      uid[index] = 'A';
      return uid.join('');
    }
    if (digit == 90  /*'Z'*/) {
      uid[index] = '0';
    } else {
      uid[index] = String.fromCharCode(digit + 1);
      return uid.join('');
    }
  }
  uid.unshift('0');
  return uid.join('');
}