mattickx/jsvat-next

Check the validity of the format of an EU VAT number

jsvat-next

A fork of https://github.com/se-panfilov/jsvat since it was unmaintained for over a year with open PR's that were important to add.

What is it?

Small library to check validity VAT numbers (European + some others counties). ([learn more][1] about VAT)

• 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

Installation:

npm i jsvat-next --save

(or yarn add jsvat-next)

For legacy versions (below v2.0.0) also possible: Bower: bower i jsvat-next --save

Getting Started

import { checkVAT, belgium, austria } from 'jsvat-next';

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

or

import { checkVAT, countries } from 'jsvat-next';
('countries');
checkVAT('BE0411905847', countries); // check against all supported countries

to check against all supported countries

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-next" 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
• Australia
• 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 Federation
• Serbia
• Slovakia republic
• Slovenia
• Spain
• Sweden
• Switzerland
• United Kingdom

How to import all countries at once?

import { checkVAT, countries } from 'jsvat-next';
// const { checkVAT, countries } = require('jsvat-next');

checkVAT('WD12345678', countries);

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>;
  calcFn: (vat: string, options?: object) => boolean; //options - isn't a mandatory param
  rules: {
    multipliers: {}; // you can leave it empty
    regex: ReadonlyArray<RegExp>;
  };
}

Example:

import { checkVAT } from 'jsvat-next';

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 / AMD / UMD / System

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 'jsvat-next';

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('jsvat-next');

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

// Legacy Frontend
<script src="whatever/jsvat-next/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-next/lib/commonjs');

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

// UMD
<script src="whatever/jsvat-next/lib/umd/index.js"></script>;

// AMD
const { checkVAT, belgium, austria } = require('jsvat-next/lib/amd');

// System
import { checkVAT, belgium, austria } from 'jsvat-next/lib/system';

How jsvat-next checks validity?

There is 2-step check:

1. 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.

2. 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.

Browsers Supports

Support only of evergreen browsers.

Legacy versions (below v2.0.0) supports all browsers down to IE9 (including IE9).