How to Export and Download CSV in Node js?

Hello Friends,

This article will provide some of the most important examples of how to export and download CSV in node js. I would like to show you export and download MySQL data to a CSV files using node.js. If you want to see an example of exporting MySQL data to a CSV file using node.js then you are in the right place.

While working on a node JS project, I had the need to pull certain data from my database and represent values in a CSV file, This guide aims at simplifying the process of creating a CSV file and making it downloadable from the client side.

Step 1: Create Node Express js App

Execute the following command on the terminal to create the node js app:

mkdir myApp

cd myApp

npm init -y

Step 2: Connect App to Database

Create a database.js file into your app root directory add the following code into it to connect your node js express app to the database:

var mysql = require('mysql');
var conn = mysql.createConnection({
    host: 'localhost', // Replace with your host name
    user: 'root',      // Replace with your database username
    password: '',      // Replace with your database password
    database: 'my-node' // // Replace with your database Name
}); 
 
conn.connect(function(err) {
    if (err) throw err;
    console.log('Database is connected successfully !');
});

module.exports = conn;

Step 3: Install express and required Modules

Execute the following command on the terminal to install express express-validator MySQL body-parser JSON web token bcryptjs cors into your node js express app:

npm install express mysql body-parser json2csv --save

Express — Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

json2csv — A JSON to CSV and CSV to JSON converter that natively supports sub-documents and auto-generates the CSV heading.

MySQL — MySQL an open-source relational database management system (RDBMS).

body-parser — Express body-parser is an npm library used to process data sent through an HTTP request body. It exposes four express middlewares for parsing text, JSON, URL-encoded and raw data set through an HTTP request body.

Step 4: Create Server.js File

Create server.js file and import express express-validator MySQL body-parser JSON web token bcryptjs cors into your server.js file; as shown below:

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var bodyParser = require('body-parser');
var db = require('./database');
var Json2csvParser = require('json2csv').Parser;
const fs = require('fs');
 
var app = express();
 
app.get('/export-csv',function(req,res){
    db.query("SELECT * FROM users", function (err, users, fields) {
        if (err) throw err;
        console.log("users:");
     
        const jsonUsers = JSON.parse(JSON.stringify(users));
        console.log(jsonUsers);
 
        // -> Convert JSON to CSV data
        const csvFields = ['id', 'name', 'email'];
        const json2csvParser = new Json2csvParser({ csvFields });
        const csv = json2csvParser.parse(jsonCustomers);
 
        console.log(csv);
 
        res.setHeader("Content-Type", "text/csv");
        res.setHeader("Content-Disposition", "attachment; filename=users.csv");
 
        res.status(200).end(csv);
    
        // -> Check 'customer.csv' file in root project folder
    });
});
 
// port must be set to 8080 because incoming http requests are routed from port 80 to port 8080
app.listen(3000, function () {
    console.log('Node app is running on port 3000');
});
 
module.exports = app;

Step 5: Start Node Express Js App Server

Execute the following command on the terminal to start the node express js server:

//run the below command

nodemon server.js

After running this command open your browser and hit

http://127.0.0.1:3000/export-csv

I hope it can help you...