// 银行号码位数分组

groupCardNumber.txt

// 银行号码位数分组
function groupCardNumber(cardNumber, digits) {
  const re = new RegExp('\\d{'+ digits + '}', 'g');
  
  return bankNumber.replace(re, function (match, offset, string) {
    if((offset + digits - 1) !== string.length - 1) {
      match = match + ' ';
    }
    return match;
  });
}