Parsing SAML x.509 Certificate in pure-Javascript

saml-x509-pki-parsing.js

const _idpX509Cert = 	_.get(resp, ['samlp:Response', 'Assertion', 0,
  'ds:Signature', 0, 'KeyInfo', 0, 'ds:X509Data', 0, 'ds:X509Certificate', 0]);

const asn1js = require('asn1js');
const pkijs = require("pkijs");
const Certificate = pkijs.Certificate;
const buf = new Buffer(_idpX509Cert, 'base64').buffer;
console.log('_idpX509Cert', _idpX509Cert);

const asn1 = asn1js.fromBER(buf);
if (asn1.offset === (-1))
  throw Error("Can not parse x.509 binary data");
const idpX509Cert = new Certificate({ schema: asn1.result });

res.end(JSON.stringify({
  idpX509Cert: idpX509Cert.toJSON(),
 }, null, 2));