se-panfilov/jsvat

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

export const ireland: Country = {
  name: 'Ireland',
  codes: ['IE', 'IRL', '372'],
  calcFn: (vat: string): boolean => {
    const { typeFormats, multipliers } = ireland.rules;
    if (!typeFormats || !typeFormats.first) return false;
    let total: string | number = 0;

    let newVat = vat;
    // If the code is type 1 format, we need to convert it to the new before performing the validation.
    if (typeFormats.first.test(vat)) {
      newVat = '0' + vat.substring(2, 7) + vat.substring(0, 1) + vat.substring(7, 8);
    }

    // Extract the next digit and multiply by the counter.
    for (let i = 0; i < 7; i++) {
      total += Number(newVat.charAt(i)) * multipliers.common[i];
    }

    // If the number is type 3 then we need to include the trailing A or H in the calculation
    if (typeFormats.third.test(newVat)) {
      // Add in a multiplier for the character A (1*9=9) or H (8*9=72)
      total += newVat.charAt(8) === 'H' ? 72 : 9;
    }

    // Establish check digit using modulus 23, and translate to char. equivalent.
    total = total % 23;
    total = total === 0 ? 'W' : String.fromCharCode(total + 64);

    // Compare it with the eighth character of the VAT number. If it's the same, then it's valid.
    const expect = newVat.slice(7, 8);
    return total === expect;
  },
  rules: {
    multipliers: {
      common: [8, 7, 6, 5, 4, 3, 2]
    },
    typeFormats: {
      first: /^\d[A-Z*+]/,
      third: /^\d{7}[A-Z][AH]$/
    },
    regex: [/^(IE)(\d{7}[A-W])$/, /^(IE)([7-9][A-Z*+)]\d{5}[A-W])$/, /^(IE)(\d{7}[A-W][AH])$/]
  }
};