@accountable/jsvat

Check the validity of the format of a VAT number. No dependencies

Disclaimer

This library is a fork of jsvat which in no longer maintained and all new pull requests to it are ignored for long time.

So in Accountable, we thought it would be great to add support for the new VAT number format and keep the library up to date and easily maintained as it is part of our day to day work.

What is it?

Small library to check validity VAT numbers (European + some others counties). (learn more about VAT)

Rewritten into Typescript 🆕
No dependencies
No http calls
2-step checks: math + regexp
Tree-shakeable
Extendable
Separate checks for valid VAT and valid VAT format
Dynamically add/remove countries with which you want to check the VAT
Detecting possible country before you finish
Typescript

Installation

via npm:

npm i @accountable/jsvat

via yarn:

yarn add @accountable/jsvat

Getting Started

check against specific countries

import { checkVAT, belgium, austria } from '@accountable/jsvat';

checkVAT('BE0411905847', [belgium]); // true: accept only Belgium VATs
checkVAT('BE0411905847', [belgium, austria]); // true: accept only Belgium or Austria VATs
checkVAT('BE0411905847', [austria]); // false: accept only Austria VATs

check against all supported countries

import { checkVAT } from '@accountable/jsvat';

checkVAT('BE0411905847'); // no need to pass countries as all supported countries will be used as default behavior

check against all supported countries except specific ones

import { checkVAT, countriesMap } from '@accountable/jsvat';

const { france, germany, ...countriesToValidate } = countriesMap;

checkVAT('BE0411905847', countriesToValidate);

Return value

checkVAT() returns VatCheckResult object:

export interface VatCheckResult {
  value?: string; // 'BE0411905847': your VAT without extra characters (like '-', spaces, etc)
  isValid: boolean; // The main result. Indicates if VAT is correct against provided countries or not
  isValidFormat: boolean; // Indicates the validation of the format of VAT only. E.g. "BE0411905847" is a valid VAT, and "BE0897221791" is not. But they both has valid format, so "isValidFormat" will return "true"
  isSupportedCountry: boolean; // Indicates if "jsvat" could recognize the VAT. Sometimes you want to understand - if it's an invalid VAT from supported country or from an unknown one
  country?: {
    // VAT's country (null if not found). By "supported" I mean imported.
    name: string; // ISO country name of VAT
    isoCode: {
      // Country ISO codes
      short: string;
      long: string;
      numeric: string;
    };
  };
}

List of supported Countries:

🇦🇩 Andorra
🇦🇹 Austria
🇧🇪 Belgium
🇧🇷 Brazil
🇧🇬 Bulgaria
🇭🇷 Croatia
🇨🇾 Cyprus
🇨🇿 Czech republic
🇩🇰 Denmark
🇪🇪 Estonia
🇪🇺 Europe
🇫🇮 Finland
🇫🇷 France
🇩🇪 Germany
🇬🇷 Greece
🇭🇺 Hungary
🇮🇪 Ireland
🇮🇹 Italy
🇱🇻 Latvia
🇱🇹 Lithuania
🇱🇺 Luxembourg
🇲🇹 Malta
🇳🇱 Netherlands
🇳🇴 Norway
🇵🇱 Poland
🇵🇹 Portugal
🇷🇴 Romania
🇷🇺 Russia
🇷🇸 Serbia
🇸🇰 Slovakia Republic
🇸🇮 Slovenia
🇪🇸 Spain
🇸🇪 Sweden
🇬🇧 United Kingdom
🇨🇭 Switzerland

Extend countries list - add your own country

You can add your own country. In general Country should implement following structure:

interface Country {
  name: string;
  codes: ReadonlyArray<string>;
  rules: {
    multipliers: {}; // you can leave it empty
    regex: ReadonlyArray<RegExp>;
  };
} & ({
    calcFn: (vat: string, options?: object) => boolean; // use this if you want to check only format of VAT
  } | {
    calcWithFormatFn: (vat: string, options?: object) => {isValid: boolean, vat: string}; // use this if you want to check format of VAT and re-format it
  })

Example:

import { checkVAT } from '@accountable/jsvat';

export const wonderland = {
  name: 'Wonderland',
  codes: ['WD', 'WDR', '999'], // This codes should follow ISO standards (short, long and numeric), but it's your own business
  calcFn: (vat) => {
    return vat.length === 10;
  },
  rules: {
    regex: [/^(WD)(\d{8})$/],
  },
};

checkVAT('WD12345678', [wonderland]); // true

About modules... ES6 / CommonJS

jsvat build includes es6, commonjs, amd, umd and system builds at the same time.

By default you will stick to es6 version for browsers and build tools (webpack, etc): which expects you to import it as

import { checkVAT, belgium, austria } from '@accountable/jsvat';

Node.js automatically will pick up CommonJS version by default. Means you could import it like:

// Modern Frontend and Node
const { checkVAT, belgium, austria } = require('@accountable/jsvat');

// Node.js
const { checkVAT, belgium, austria } = require('@accountable/jsvat');

// Legacy Frontend
<script src='whatever/jsvat/lib/umd/index.js'></script>;

Alternatively you can specify which module system you do want, e.g.:

// CommonJS (i.g nodejs)
const { checkVAT, belgium, austria } = require('jsvat/lib/commonjs');

// ES6
import { checkVAT, belgium, austria } from 'jsvat/lib/es6';

How `@accountable/jsvat` checks validity?

There is 2-step check:

Compare with list of Regexps;

For example regexp for austria is /^(AT)U(\d{8})$/.

Looks like ATU99999999 is valid (it's satisfy the regexp), but actually it's should be invalid.

Some magic mathematical counting;

Here we make some mathematical calculation (different for each country). After that we may be sure that ATU99999999and for example ATV66889218 isn't valid, but ATU12011204 is valid.

Note: VAT numbers of some countries should ends up with special characters. Like '01' for Sweden or "L" for Cyprus. If 100% real VAT doesn't fit, try to add proper appendix.

Accountable-SA/accountable-jsvat