A method to wrap your node application with a mysql pool.

mysqlConnector.js

/*
Created with refrence from
https://gist.github.com/binki/52662f18ae6fc89b18b020b89aa4e1cd
http://www.madhur.co.in/blog/2016/09/05/nodejs-connection-pooling.html
*/
const mysql = require('mysql'); // import

const pool = mysql.createPool({ // create pool instance
    host: "*",
    user: "*",
    password: "*",
    connectionLimit: 100, //important
});

/*
parse successful queries by converting RowDataPacket to JS Object
*/
const onSuccess = (rows) => {
    return (
        JSON.parse(
            JSON.stringify(rows)
           )
    )
}

const hitQuery = (query) => 
    new Promise((resolve, reject) => {
        pool.query(query, (ex, rows) => {
            (
                (ex) ? reject(ex) :
                resolve(rows)
                )
            });
        })
    .then((rows) => onSuccess(rows));


module.exports = hitQuery;

query.js

const hitQuery = require('./mysqlConnector.js');

query = (` select * from users where username="sam"`);

hitQuery(query)
.then(response => console.log(response))
.catch(e => console.log(e))

No problem! Thanks for updating your gist!