isIBAN.js

import assertString from './util/assertString';
import includes from './util/includesArray';

/**
 * List of country codes with
 * corresponding IBAN regular expression
 * Reference: https://en.wikipedia.org/wiki/International_Bank_Account_Number
 */
const ibanRegexThroughCountryCode = {
  AD: /^(AD[0-9]{2})\d{8}[A-Z0-9]{12}$/,
  AE: /^(AE[0-9]{2})\d{3}\d{16}$/,
  AL: /^(AL[0-9]{2})\d{8}[A-Z0-9]{16}$/,
  AT: /^(AT[0-9]{2})\d{16}$/,
  AZ: /^(AZ[0-9]{2})[A-Z0-9]{4}\d{20}$/,
  BA: /^(BA[0-9]{2})\d{16}$/,
  BE: /^(BE[0-9]{2})\d{12}$/,
  BG: /^(BG[0-9]{2})[A-Z]{4}\d{6}[A-Z0-9]{8}$/,
  BH: /^(BH[0-9]{2})[A-Z]{4}[A-Z0-9]{14}$/,
  BR: /^(BR[0-9]{2})\d{23}[A-Z]{1}[A-Z0-9]{1}$/,
  BY: /^(BY[0-9]{2})[A-Z0-9]{4}\d{20}$/,
  CH: /^(CH[0-9]{2})\d{5}[A-Z0-9]{12}$/,
  CR: /^(CR[0-9]{2})\d{18}$/,
  CY: /^(CY[0-9]{2})\d{8}[A-Z0-9]{16}$/,
  CZ: /^(CZ[0-9]{2})\d{20}$/,
  DE: /^(DE[0-9]{2})\d{18}$/,
  DK: /^(DK[0-9]{2})\d{14}$/,
  DO: /^(DO[0-9]{2})[A-Z]{4}\d{20}$/,
  DZ: /^(DZ\d{24})$/,
  EE: /^(EE[0-9]{2})\d{16}$/,
  EG: /^(EG[0-9]{2})\d{25}$/,
  ES: /^(ES[0-9]{2})\d{20}$/,
  FI: /^(FI[0-9]{2})\d{14}$/,
  FO: /^(FO[0-9]{2})\d{14}$/,
  FR: /^(FR[0-9]{2})\d{10}[A-Z0-9]{11}\d{2}$/,
  GB: /^(GB[0-9]{2})[A-Z]{4}\d{14}$/,
  GE: /^(GE[0-9]{2})[A-Z0-9]{2}\d{16}$/,
  GI: /^(GI[0-9]{2})[A-Z]{4}[A-Z0-9]{15}$/,
  GL: /^(GL[0-9]{2})\d{14}$/,
  GR: /^(GR[0-9]{2})\d{7}[A-Z0-9]{16}$/,
  GT: /^(GT[0-9]{2})[A-Z0-9]{4}[A-Z0-9]{20}$/,
  HR: /^(HR[0-9]{2})\d{17}$/,
  HU: /^(HU[0-9]{2})\d{24}$/,
  IE: /^(IE[0-9]{2})[A-Z]{4}\d{14}$/,
  IL: /^(IL[0-9]{2})\d{19}$/,
  IQ: /^(IQ[0-9]{2})[A-Z]{4}\d{15}$/,
  IR: /^(IR[0-9]{2})0\d{2}0\d{18}$/,
  IS: /^(IS[0-9]{2})\d{22}$/,
  IT: /^(IT[0-9]{2})[A-Z]{1}\d{10}[A-Z0-9]{12}$/,
  JO: /^(JO[0-9]{2})[A-Z]{4}\d{22}$/,
  KW: /^(KW[0-9]{2})[A-Z]{4}[A-Z0-9]{22}$/,
  KZ: /^(KZ[0-9]{2})\d{3}[A-Z0-9]{13}$/,
  LB: /^(LB[0-9]{2})\d{4}[A-Z0-9]{20}$/,
  LC: /^(LC[0-9]{2})[A-Z]{4}[A-Z0-9]{24}$/,
  LI: /^(LI[0-9]{2})\d{5}[A-Z0-9]{12}$/,
  LT: /^(LT[0-9]{2})\d{16}$/,
  LU: /^(LU[0-9]{2})\d{3}[A-Z0-9]{13}$/,
  LV: /^(LV[0-9]{2})[A-Z]{4}[A-Z0-9]{13}$/,
  MA: /^(MA[0-9]{26})$/,
  MC: /^(MC[0-9]{2})\d{10}[A-Z0-9]{11}\d{2}$/,
  MD: /^(MD[0-9]{2})[A-Z0-9]{20}$/,
  ME: /^(ME[0-9]{2})\d{18}$/,
  MK: /^(MK[0-9]{2})\d{3}[A-Z0-9]{10}\d{2}$/,
  MR: /^(MR[0-9]{2})\d{23}$/,
  MT: /^(MT[0-9]{2})[A-Z]{4}\d{5}[A-Z0-9]{18}$/,
  MU: /^(MU[0-9]{2})[A-Z]{4}\d{19}[A-Z]{3}$/,
  MZ: /^(MZ[0-9]{2})\d{21}$/,
  NL: /^(NL[0-9]{2})[A-Z]{4}\d{10}$/,
  NO: /^(NO[0-9]{2})\d{11}$/,
  PK: /^(PK[0-9]{2})[A-Z0-9]{4}\d{16}$/,
  PL: /^(PL[0-9]{2})\d{24}$/,
  PS: /^(PS[0-9]{2})[A-Z]{4}[A-Z0-9]{21}$/,
  PT: /^(PT[0-9]{2})\d{21}$/,
  QA: /^(QA[0-9]{2})[A-Z]{4}[A-Z0-9]{21}$/,
  RO: /^(RO[0-9]{2})[A-Z]{4}[A-Z0-9]{16}$/,
  RS: /^(RS[0-9]{2})\d{18}$/,
  SA: /^(SA[0-9]{2})\d{2}[A-Z0-9]{18}$/,
  SC: /^(SC[0-9]{2})[A-Z]{4}\d{20}[A-Z]{3}$/,
  SE: /^(SE[0-9]{2})\d{20}$/,
  SI: /^(SI[0-9]{2})\d{15}$/,
  SK: /^(SK[0-9]{2})\d{20}$/,
  SM: /^(SM[0-9]{2})[A-Z]{1}\d{10}[A-Z0-9]{12}$/,
  SV: /^(SV[0-9]{2})[A-Z0-9]{4}\d{20}$/,
  TL: /^(TL[0-9]{2})\d{19}$/,
  TN: /^(TN[0-9]{2})\d{20}$/,
  TR: /^(TR[0-9]{2})\d{5}[A-Z0-9]{17}$/,
  UA: /^(UA[0-9]{2})\d{6}[A-Z0-9]{19}$/,
  VA: /^(VA[0-9]{2})\d{18}$/,
  VG: /^(VG[0-9]{2})[A-Z]{4}\d{16}$/,
  XK: /^(XK[0-9]{2})\d{16}$/,
};


/**
 * Normalize an IBAN string.
 *
 * If `strip` is true, removes characters matching `pattern` (by default, any
 * non-alphanumeric). Converts the resulting string to uppercase.
 *
 * @param {string} str - IBAN string to normalize.
 * @param {boolean} strip - Whether to remove characters matching `pattern`.
 * @param {RegExp} pattern=/[^A-Z0-9]+/gi - Pattern used when stripping.
 * @return {string} Normalized (uppercase) IBAN string.
 */
function normalizeIbanString(str, strip, pattern = /[^A-Z0-9]+/gi) {
  return (strip ? str.replace(pattern, '') : str).toUpperCase();
}

/**
 * Check if the country codes passed are valid using the
 * ibanRegexThroughCountryCode as a reference
 *
 * @param {array} countryCodeArray
 * @return {boolean}
 */

function hasOnlyValidCountryCodes(countryCodeArray) {
  const countryCodeArrayFilteredWithObjectIbanCode = countryCodeArray
    .filter(countryCode => !(countryCode in ibanRegexThroughCountryCode));

  if (countryCodeArrayFilteredWithObjectIbanCode.length > 0) {
    return false;
  }

  return true;
}

/**
 * Check whether string has correct universal IBAN format
 * The IBAN consists of up to 34 alphanumeric characters, as follows:
 * Country Code using ISO 3166-1 alpha-2, two letters
 * check digits, two digits and
 * Basic Bank Account Number (BBAN), up to 30 alphanumeric characters.
 * NOTE: Permitted IBAN characters are: digits [0-9] and the 26 latin alphabetic [A-Z]
 *
 * @param {string} str - string under validation
 * @param {boolean} options.strip - If truthy, whitespace and hyphens are removed before validation.
 * @param {string[]} options.whitelist - Optional set of allowed ISO country codes
 * (e.g., ["DE","GB","CH"]). If present, IBANs for other countries are rejected.
 * @param {string[]} options.blacklist - Optional set of disallowed ISO country codes
 * (e.g., ["DE","GB","CH"]). If present, IBANs for these countries are rejected.
 * @return {boolean}
 */
function hasValidIbanFormat(str, options) {
  // Strip white spaces and hyphens
  const strippedStr = normalizeIbanString(str, options.strip, /[\s\-]+/gi);
  const isoCountryCode = strippedStr.slice(0, 2).toUpperCase();

  const isoCountryCodeInIbanRegexCodeObject = isoCountryCode in ibanRegexThroughCountryCode;

  if (options.whitelist) {
    if (!hasOnlyValidCountryCodes(options.whitelist)) {
      return false;
    }

    const isoCountryCodeInWhiteList = includes(options.whitelist, isoCountryCode);

    if (!isoCountryCodeInWhiteList) {
      return false;
    }
  }

  if (options.blacklist) {
    const isoCountryCodeInBlackList = includes(options.blacklist, isoCountryCode);

    if (isoCountryCodeInBlackList) {
      return false;
    }
  }

  return (isoCountryCodeInIbanRegexCodeObject) &&
    ibanRegexThroughCountryCode[isoCountryCode].test(strippedStr);
}

/**
   * Check whether string has valid IBAN Checksum
   * by performing basic mod-97 operation and
   * the remainder should equal 1
   * -- Start by rearranging the IBAN by moving the four initial characters to the end of the string
   * -- Replace each letter in the string with two digits, A -> 10, B = 11, Z = 35
   * -- Interpret the string as a decimal integer and
   * -- compute the remainder on division by 97 (mod 97)
   * Reference: https://en.wikipedia.org/wiki/International_Bank_Account_Number
   *
   * @param {string} str
   * @param {boolean} strip - Whether to strip the string of non-alphanumeric characters
   * @return {boolean}
   */
function hasValidIbanChecksum(str, strip) {
  const strippedStr = normalizeIbanString(str, strip, /[^A-Z0-9]+/gi);
  const rearranged = strippedStr.slice(4) + strippedStr.slice(0, 4);
  const alphaCapsReplacedWithDigits = rearranged.replace(/[A-Z]/g, char => char.charCodeAt(0) - 55);

  const remainder = alphaCapsReplacedWithDigits.match(/\d{1,7}/g)
    .reduce((acc, value) => Number(acc + value) % 97, '');

  return remainder === 1;
}

export default function isIBAN(str, options = {}) {
  const optionsWithDefaults = { strip: true, ...options };

  assertString(str);

  return hasValidIbanFormat(str, optionsWithDefaults)
    && hasValidIbanChecksum(str, optionsWithDefaults.strip);
}

export const locales = Object.keys(ibanRegexThroughCountryCode);