Javascript IBAN validator displaying failure reasons

If you need a Javascript library to validate IBAN bank numbers, ibantools seems the most updated and stable library at the moment.

In case of validation errors, it returns error codes that internally have a meaning.

If you need to display in the logs the error names (e.g. WrongBBANLengt/WrongBBANFormat/WrongIBANChecksum) instead of the numeric code, you can use this code that wraps and rethrow the errors with their corresponding name.

import * as ibantools from 'ibantools';
import { ValidationErrorsIBAN } from 'ibantools';
import { BadRequestError } from '../exceptions/BadRequestError.js';

/**
 * @param {string} iban
 * @returns {boolean}
 *
 * @throws BadRequestError
 */
export const validateIBAN = (iban) => {
  let result = {};
  try {
    result = ibantools.validateIBAN(iban);
    console.log(`iban ${iban} valid`);
  } catch (error) {
    throw new BadRequestError(`Invalid IBAN, ${error}`);
  }

  if (!result.valid) {
    const errorsCsv = result.errorCodes.map(code => ValidationErrorsIBAN[code]).join(', ');
    throw new BadRequestError(`Invalid IBAN, ${errorsCsv}`);
  }

  return true;
};

And this is the unit test

import { validateIBAN } from 'ibanValidator.js';

describe('isIBANValid', () => {
  test.each([
    { iban: 'BE68539007547034', expectedResult: true },
    // add more here ....
    // invalid ones
    { iban: 'invalid iban', expectedResult: false, expectedError: 'Invalid IBAN, NoIBANCountry' },
    { iban: 'AAAA088110105031K002U', expectedResult: false, expectedError: 'Invalid IBAN, NoIBANCountry' },
    {
      iban: 'LI31088110105031K001G1',
      expectedResult: false,
      expectedError: 'Invalid IBAN, WrongBBANLength, WrongBBANFormat, WrongIBANChecksum',
    },
  ])(
    'returns $expectedResult for IBAN $iban',
    ({ iban, expectedResult, expectedError }) => {
      if (expectedResult) {
        expect(validateIBAN(iban)).toBe(true);
      } else {
        expect(() => validateIBAN(iban)).toThrowError(expectedError);
      }
    },
  );
});