expressjs API with tedious and SQL server connection

In below example I have used node.js, express js and tedious.
for more details about tedious go to tedious

/*
* Install below packages using node package manager
* 1) $ npm install express --save
* 2) $ npm install tedious --save
*
* Run Application using
* $ node index.js
/

                (function () {
    var express = require('express')
    var app = express()
    
    app.get('/', function (req, res) {
    
        // tedious package is used for SQL server connection
        var Connection = require('tedious').Connection;
        var Request = require('tedious').Request;
    
        // add SQL server configurations here
        var config = {
            server: '[server_name]',
            userName: '[user_name]',
            password: '[password]',        
            options: {            
                instanceName: '[instance_name]',
                database: '[database_name]'            
            }
        }
    
        var connection = new Connection(config);
    
        connection.on('connect', function (err,resp) {
            if (err) {
                console.log(err);
            } else {
                executeStatement(resp);            
            }
        });
    
        function executeStatement(resp) {
            // add SQL query here
            request = new Request('select * from [table_name] with (nolock)', function (err, rowCount) {
                if (err) {
                    console.log(err);
                } else {
                    console.log(rowCount + ' rows');
                }
                connection.close();
                // return rowCount from API
                res.json(rowCount);
            });
    
            // row iteratore for result
            request.on('row', function (columns) {
                columns.forEach(function (column) {
                    if (column.value === null) {
                        console.log('NULL');
                    } else {
                        console.log(column.value);
                    }
                });
            });
            
            // execute query
            connection.execSql(request);        
        }
    });
    
    var server = app.listen(5000, function () {
        console.log('Server is running..');
    });
})();