jsvat: A JavaScript repository from Gab-Metzger

jsvat

Check the validity of the format of an EU VAT number. No dependencies.

What is it?

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

(or yarn add jsvat)

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

Getting Started

import { checkVAT, belgium, austria } from '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

import { checkVAT, countries } from 'jsvat';
('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" 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
Switzerland
Cyprus
Czech Republic
Germany
Denmark
Greece
Spain
Europe
Estonia
Finland
France
United Kingdom
Croatia
Hungary
Ireland
Italy
Latvia
Lithuania
Luxembourg
Malta
Netherlands
Norway
Poland
Portugal
Romania
Russia Federation
Serbia
Slovenia
Slovakia republic
Sweden

How to import all countries at once?

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

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';

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';

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');

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

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

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

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

How 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.

Browsers Supports

Support only of evergreen browsers.

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

LICENSE

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Gab-Metzger/jsvat