Problem with mysql module

[carambuco]

Hi!
I'm experiencing trouble trying to use node-mysql within a pixiedust-node project.

The cell setup is the following:

import pixiedust_node
npm.install('mysql')

This works as expected showing the logos of both pixiedust and pixiedust node and then the stats of the module install.
The problem comes with the nodejs part. The code works perfectly in a nodejs project, but not within pixiedust-node:

%%node
var mysql = require('mysql');
var dburl = 'database-url.com';
var con = mysql.createConnection({
  host: dburl,
  user: 'dbuser',
  password: 'dbpassword',
  database: 'dbdatabase'
});
con.connect(function(err) {
    if (err) throw err;
});
var query ='SELECT user_created_date from user LIMIT 100';
con.query(query, function (err, result, fields) {
            if (err) throw err;
            console.log(result);
});
con.end();

I write it down here as a single block, but I've tried it in different cell layouts to find more precisely where the error is located. And it is located in the mysql.createConnection() call:

... ... ... ... ... TypeError: Converting circular structure to JSON
at JSON.stringify (<anonymous>)
at globalVariableChecker (/home/javier/anaconda3/lib/python3.7/site-packages/pixiedust_node/pixiedustNodeRepl.js:26:22)
at REPLServer.writer (/home/javier/anaconda3/lib/python3.7/site-packages/pixiedust_node/pixiedustNodeRepl.js:67:5)
at finish (repl.js:683:38)
at finishExecution (repl.js:310:7)
at REPLServer.defaultEval (repl.js:396:7)
at bound (domain.js:395:14)
at REPLServer.runBound [as eval] (domain.js:408:12)
at REPLServer.onLine (repl.js:639:10)
at REPLServer.emit (events.js:182:13)
/home/javier/anaconda3/lib/python3.7/site-packages/pixiedust_node/pixiedustNodeRepl.js:26
const j = JSON.stringify(r.context[v]);
^
TypeError: Converting circular structure to JSON
at JSON.stringify (<anonymous>)
at Timeout.globalVariableChecker [as _onTimeout] (/home/javier/anaconda3/lib/python3.7/site-packages/pixiedust_node/pixiedustNodeRepl.js:26:22)
at ontimeout (timers.js:436:11)
at tryOnTimeout (timers.js:300:5)
at unrefdHandle (timers.js:520:7)
at Timer.processTimers (timers.js:222:12)

[glynnbird]

Try declaring your "global" things as const instead of var. i.e. your identifiers mysql, dburl, con and query can all be consts instead of vars.