mustangjs

TypeScript port of mustangproject — a library for creating, parsing, and validating EN16931 e-invoices (ZUGFeRD, Factur-X, XRechnung).

Install

npm install @aifind/mustangjs

Usage

import { Invoice, Item, Product, TradeParty, Big } from '@aifind/mustangjs';
import { ZUGFeRD2PullProvider, Profiles } from '@aifind/mustangjs';

const invoice = new Invoice()
  .setNumber('INV-001')
  .setIssueDate(new Date())
  .setSender(new TradeParty('Seller GmbH', 'Str. 1', '10115', 'Berlin', 'DE').addVATID('DE123'))
  .setRecipient(new TradeParty('Buyer AG', 'Str. 2', '80331', 'Munich', 'DE'))
  .addItem(new Item(new Product('Service', '', 'C62', new Big(19)), new Big(100), new Big(1)));

const provider = new ZUGFeRD2PullProvider();
provider.setProfile(Profiles.getByName('EN16931'));
provider.generateXML(invoice);
const xml = provider.getXML(); // CII XML string

Parse

import { ZUGFeRDInvoiceImporter, CalculatedInvoice } from '@aifind/mustangjs';

const importer = new ZUGFeRDInvoiceImporter(xmlString);
const ci = new CalculatedInvoice();
importer.extractInto(ci);
console.log(ci.getGrandTotal().toString());

Validate

Validate invoice XML against official EN16931 and XRechnung Schematron rules using XMLValidator.

import { XMLValidator } from '@aifind/mustangjs';

const validator = new XMLValidator();
const result = await validator.validate(xmlString);

result.isValid();          // true if no errors
result.getErrors();        // ValidationResultItem[]
result.getWarnings();      // warnings (non-blocking)
result.hasRule('BR-02');   // check specific rule

Format (CII/UBL) and profile are auto-detected from the XML. You can override:

import { XMLValidator, Profiles } from '@aifind/mustangjs';

const result = await validator.validate(xmlString, {
  profile: Profiles.getByName('XRECHNUNG'),  // override auto-detected profile
  skipProgrammatic: true,                     // Schematron only (recommended)
});

There is also a lower-level InvoiceValidator for programmatic rule checks on Invoice objects (without XML/Schematron):

import { InvoiceValidator, Profiles } from '@aifind/mustangjs';

const validator = new InvoiceValidator(Profiles.getByName('EN16931'));
const result = validator.validate(invoice);

Schematron rules

Validation is powered by pre-compiled Schematron XSLT stylesheets (via saxon-js):

Ruleset	Format	Covers
EN16931-CII	CII	Core EN16931 business rules for ZUGFeRD/Factur-X
EN16931-UBL	UBL	Core EN16931 business rules (incl. PEPPOL BIS)
XRechnung-CII	CII	German XRechnung-specific rules (v3.0)
XRechnung-UBL	UBL	German XRechnung-specific rules (v3.0)

The SEF files live in src/validation/schematron/. See SCHEMATRON.md for how to update them when new rule versions are released.

Supported formats

• CII (Cross-Industry Invoice): ZUGFeRD 2.x, Factur-X
• UBL (Universal Business Language): XRechnung

Profiles

MINIMUM, BASICWL, BASIC, EN16931, EXTENDED, XRECHNUNG

Build & test

npm run build
npm test

License

This project is licensed under the Apache License 2.0. Third-party runtime dependencies and bundled validation artifacts are under their own licenses. See NOTICE.