10 进制转 n(2~36) 进制

const baseConverter = function (num, n=2) {
  const arr = [];
  const digits = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  if (!(n >= 2 && n <= 36)) {
    return '';
  }
  while (num > 0) {
    arr.push(num % n | 0);
    num = num / n | 0;
  }
  return arr.reverse().map(v => digits[v]).join('');
}