import Afip from '@afipsdk/afip.js';

const afip = new Afip({
  access_token: 'YOUR_ACCESS_TOKEN',
  CUIT: 20409378472,
});

const invoice = await afip.ElectronicBilling.createVoucher({
  CantReg: 1,
  PtoVta: 1,
  CbteTipo: 6,
  Concepto: 1,
  DocTipo: 80,
  DocNro: 20111111112,
  ImpTotal: 121,
  ImpNeto: 100,
  ImpIVA: 21,
});

console.log(invoice.CAE, invoice.CAEFchVto);