var connection = mysql.createConnection({
  host     : 'example.org',
  user     : 'bob',
  password : 'secret'
});

var config = require('./config.js');
var mysql = require('mysql');
var connection = mysql.createConnection(config.connectionString);

exports.login = function() ...

var mysql = require('mysql');

var pool = mysql.createPool({
    connectionLimit: 100,
    host: 'localhost',
    user: 'xxxxx',
    password: 'yyyyy',
    database: 'zzzzz',
    debug: false
});

module.exports = pool

var express = require('express');
var router = express.Router();

var pool = require('./utils/database');

router.get('/', function(req, res) {

    pool.getConnection(function(err, connection) {

        // do whatever you want with your connection here

        connection.release();

    });
});

module.exports = router;

var mysql = require('mysql');

var pool = mysql.createPool({
    connectionLimit: 100,
    host: 'localhost',
    user: 'xxxxx',
    password: 'yyyyy',
    database: 'zzzzz',
    debug: false
});

var getConnection = function(callback) {
    pool.getConnection(function(err, connection) {
        callback(err, connection);
    });
});

module.exports = getConnection;

var express = require('express');
var router = express.Router();

var createConnection = require('./utils/database');

router.get('/', function(req, res) {

    createConnection(function(err, connection) {

        // do whatever you want with your connection here

        connection.release();

    });
});

module.exports = router;

var mysql = require("mysql");
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'user',
  password : 'password'
});
connection.connect();
module.exports = connection;

var connection = require("./connection.js");
connection.query('some query', callback);