jsforce with jwt

org_connection.js

const jsforce = require('jsforce');
const jwt = require("salesforce-jwt-bearer-token-flow");

// create the connection to the org
let conn = new jsforce.Connection();

// load the private key for the token
let privateKey = require('fs').readFileSync('./server.key', 'utf8');

jwt.getToken({
  iss: process.env.CLIENT_ID,
  sub: process.env.USERNAME,
  aud: process.env.LOGIN_URL,
  privateKey: privateKey
}, function(err, response) {
    if (err) {
      console.error(err);
    } else {
      conn.initialize({
        instanceUrl: response.instance_url,
        accessToken: response.access_token
      });
      console.log('Successfully connected to Org');
    }
  }
);

module.exports = conn;