Creating id_token with Javascript

var jwt = require('jsonwebtoken');
var fs = require("fs");

// sign with RSA SHA256
var privateKey = fs.readFileSync('<env><partner_name>privatekey.pem');

const idToken = jwt.sign(
    { stockal_username: '<stockal-customer-id>' }, 
    privateKey, 
    { 
        algorithm: 'RS512', 
        expiresIn: "60", 
        audience : 'stockal.com', 
        issuer : '<YOUR_PARTNER_CODE>' 
    });

console.log(idToken);