salix/modules/supplier/back/models/supplier-account.js

const validateIban = require('vn-loopback/util/validateIban');

module.exports = Self => {
    Self.validateAsync('iban', ibanValidation, {
        message: 'The IBAN does not have the correct format'
    });

    async function ibanValidation(err, done) {
        let filter = {
            fields: ['code'],
            where: {id: this.countryFk}
        };
        let country = await Self.app.models.Country.findOne(filter);
        let code = country ? country.code.toLowerCase() : null;
        if (code != 'es')
            return done();

        if (!validateIban(this.iban))
            err();
        done();
    }
};