cz-bank-account-validator/src/index.js

A small and handy library to validate CZ bank account numbers. Running in a browser, in Node.js and also as an ES6 module.

import { bankCodes } from './bankCodes';
import { getBankAccountGroups, mod11 } from './util';

export const getAllBankCodes = () => {
    return bankCodes;
};

/**
 * http://www.zlatakoruna.info/zpravy/ucty/cislo-uctu-v-cr
 * @param bankAccount
 */
export const validate = (bankAccount = '') => {
    if (typeof bankAccount !== 'string' || bankAccount.length < 1) {
        return false;
    }

    const bankCodeKeys = Object.keys(getAllBankCodes());
    const bankAccountMatchedGroups = getBankAccountGroups(bankAccount);

    if (bankAccountMatchedGroups) {
        const { prefixCode, accountNumber, bankCode } = bankAccountMatchedGroups;

        const prefixCodeValid = prefixCode ? mod11(prefixCode) : true; // can be empty
        const accountNumberValid = accountNumber ? mod11(accountNumber) : false;
        const bankCodeValid = bankCode ? bankCodeKeys.includes(bankCode) : false;

        return prefixCodeValid && accountNumberValid && bankCodeValid;
    }

    return false;
};

export const getAccountPrefix = (bankAccount) => {
    if (validate(bankAccount)) {
        const bankAccountMatchedGroups = getBankAccountGroups(bankAccount);
        return bankAccountMatchedGroups?.prefixCode ?? null;
    }
    return null;
};

export const getAccountNumber = (bankAccount) => {
    if (validate(bankAccount)) {
        const bankAccountMatchedGroups = getBankAccountGroups(bankAccount);
        return bankAccountMatchedGroups?.accountNumber ?? null;
    }
    return null;
};

export const getBankCode = (bankAccount) => {
    if (validate(bankAccount)) {
        const bankAccountMatchedGroups = getBankAccountGroups(bankAccount);
        return bankAccountMatchedGroups?.bankCode ?? null;
    }
    return null;
};