Node.js mssql Global connection already exists connection pool memory leak - sql

Question

New to Node. I have looked at some other questions, and haven't found a direct answer. I'm creating a module for a simple Sql data call, but am getting the "Global connection already exists" error. I believe my solution lies in using a connectionPool, but I am uncertain of how to create a connection pool or if I'm doing it correctly. Any help is appreciated. I have removed any sensitive login data as well.
UPDATE: by switching my sql.close() and putting it before my onDone&&onDone() callback function, I now am receiving the correct data, but node is now giving warnings of " Warning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit"
What's not working: I can successfully run my first call, but then every call after that returns nothing. I have verified using SQL profiler that only one call is being made to the server. So I believe something in my code is bypassing the second call and returning a null result set?
const self = {};
// NPM package that supports accessing Microsoft SQL databases from node.
let sql = require('mssql');
let debug = false;
let connection;
// configure SQL Connection. The credentials below should be handled more securely.
// While this backend code is not accessible via public web accesses, it will be in
// GitHub.
let config = {
domain: "hidden",
user: "hidden",
password: 'hidden',
server: 'hidden',
database: 'hidden',
options: {
encrypt: false // Use this if you're on Windows Azure
}
};
self.getSQLData = function getSQLData (sprocInfo,onDone,onRow) {
// Connect to SQL Server.
if(debug) console.log("Hit SQL Function \n");
if (typeof(sprocInfo.parameters) === 'object' && Array.isArray(sprocInfo.parameters)){
if(debug)console.log("Passed array check");
if(sprocInfo.database) config.database = sprocInfo.database;
if(connection && connection._connected){
if(debug) console.log("Inside SQL Connection");
const request = new sql.Request(connection); //create a new request
request.stream = true;
var results = [];
//put all parameters as input parameters to sql call
sprocInfo.parameters.forEach(function(element){
request.input(element.parameterName.toString(),sql.NVarChar,element.parameterValue);
//NEED to remove hard typing of Integers. Maybe case statement based on typeof??
});
request.on('row', row => {
results.push(row);
onRow && onRow(row);
});
request.on('done', result => {
// console.log("Result in request.on done"+JSON.stringify(result));
onDone && onDone(results);
sql.close();
});
request.on('error', err => {
// May be emitted multiple times
if ( debug ) console.log('error');
if ( debug ) console.log('the error is: ' + err);
});
request.execute(sprocInfo.procedure)
} else {
connection = sql.connect(config, err => {
if(debug) console.log("Inside SQL Connection");
const request = new sql.Request(); //create a new request
request.stream = true;
var results = [];
//put all parameters as input parameters to sql call
sprocInfo.parameters.forEach(function(element){
request.input(element.parameterName.toString(),sql.NVarChar,element.parameterValue);
//NEED to remove hard typing of Integers. Maybe case statement based on typeof??
});
request.on('row', row => {
results.push(row);
onRow && onRow(row);
});
request.on('done', result => {
// console.log("Result in request.on done"+JSON.stringify(result));
onDone && onDone(results);
sql.close();
});
request.on('error', err => {
// May be emitted multiple times
if ( debug ) console.log('error');
if ( debug ) console.log('the error is: ' + err);
});
request.execute(sprocInfo.procedure)
});
}
sql.on('error', err => {
console.log("Error: Failed to connect to SQL Server");
});
} else {
throw new Error ("Parameters is not an array");
}
};
module.exports = self;