se-panfilov/jsvat

import { Country } from '../jsvat';

export const greece: Country = {
  name: 'Greece',
  codes: ['GR', 'GRC', '300'],
  calcFn: (vat: string): boolean => {
    let total = 0;

    // eight character numbers should be prefixed with an 0.
    const newVat = vat.length === 8 ? '0' + vat : vat;

    // Extract the next digit and multiply by the counter.
    for (let i = 0; i < 8; i++) {
      total += Number(newVat.charAt(i)) * greece.rules.multipliers.common[i];
    }

    // Establish check digit.
    total = total % 11;
    total = total > 9 ? 0 : total;

    // Compare it with the last character of the VAT number. If it's the same, then it's valid.
    const expect = Number(newVat.slice(8, 9));
    return total === expect;
  },
  rules: {
    multipliers: {
      common: [256, 128, 64, 32, 16, 8, 4, 2]
    },
    regex: [/^(EL)(\d{9})$/]
  }
};