Node.js-Create an online chat application
Tags: webdev, javascript, node
Published: 2023-02-26 06:07:36

## What is Node.js?

Node.js is an open-source, cross-platform, back-end JavaScript runtime environment built on the V8 engine. It enables developers to run JavaScript on the server-side, outside of the browser.
Node.js provides an event-driven, non-blocking I/O model, which makes it an excellent choice for building real-time, data-intensive applications like online chat applications. Also, Node.js provides a vast library of modules that can be used to build complex applications.

In this blog post, I'll explore why Node.js is a great platform for building an online chat application, and take a look at some of the tools and technologies you can use to get started.



### Performance

One of the key advantages of Node.js is its ability to handle a large number of simultaneous connections with high throughput. This makes it an ideal platform for building real-time applications, such as chat applications, gaming platforms, and streaming services. Node.js's performance and scalability make it a great choice for building an online chat application that can handle a large number of users.


### Community

Node.js has a large and active community of developers that contribute to its development and maintenance. This community has developed a wide range of third-party packages and modules that can be easily installed and used in Node.js applications.


### Development tools

Node.js has a wide range of tools and frameworks available for developing web applications, from web frameworks to database libraries and testing tools. I will introduce some tools that I am going to use to build the application.


#### npm - Node Package Manager

To build an online chat application with Node.js, you'll need some tools and technologies. One of the most important tools is the Node Package Manager (npm), which allows you to easily manage and install dependencies for your projects. You can use npm to find and install packages from the official npm registry or from a local or remote repository.
To install a package using npm, simply run the following command:

```
npm install package-name
```


#### Express.js

Express.js is a popular open-source framework for Node.js that simplifies the process of building web applications by providing a robust set of features and tools. It is designed to provide a minimalist approach to building web applications and APIs, making it easy for developers to build scalable and high-performance applications. Express.js is built on top of Node.js, providing access to all of the powerful features and functionality of the Node.js runtime.

```
npm install express
```

#### Socket.IO
Socket.IO is a popular open-source library for Node.js that enables real-time, bidirectional communication between the client and server. It is designed to enable real-time, event-based communication between the client and server, making it ideal for building applications that require real-time data exchange, such as online chat applications, multiplayer games, and collaborative editing tools. To install Express.js, use the following command:

```
npm install socket.io
```

#### MySQL

MySQL is a popular relational database management system that is often used with Node.js. It provides a flexible and scalable way to store and manage data. To use MySQL with Node.js, you can use the official MySQL driver for Node.js, or use an ORM (Object-Relational Mapping) library such as Sequelize.
To use the official MySQL driver for Node.js, first need to install the mysql package using npm:

```
npm install mysql2
```

Then, you can create a connection to your MySQL database and execute queries using the following code:

```

const mysql = require('mysql2');

const connection = mysql.createConnection({
    host: 'localhost',
    user: 'username',

});
```

#### React

React is an open-source JavaScript library used for building user interfaces (UIs). It was developed by Facebook and released in 2013. React allows developers to create reusable UI components that can be used to build complex UIs for web and mobile applications. I will use React to build the UI for the Online Chat Application.

### Start with "Hello, World!"

The project could be create in command prompt or terminal. But Work with a Code Editor will save more works. Here will be an example to create "Hello, world!" to show on webpage with VScode.

**1.** Open VS Code and create a new folder Called hello_world 

**2.** in the folder in VS Code and create a new file called index.js.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/k0jlk1vu6se2zvjxq1sv.png)

**3.** Write the following code to start the server on local machine and listen the port 3000, and send the request to display "Hello World!"

```
const http = require('http');

const server = http.createServer((req, res) => {
  res.end('Hello, World!');
});

server.listen(3000, () => {
  console.log('Server running on port 3000');
});
```

In this example, I first import the http module and create a new server using the createServer method. The createServer method takes a callback function that is called every time a request is made to the server. The callback function takes two arguments: req (the incoming request) and res (the outgoing response).

Then, I simply send the string "Hello, World!" as the response using the end method of the res object. We then start the server on port 3000 and log a message to the console to indicate that the server is running.

**4.** Open the terminal in VS Code by pressing Ctrl + ~ (Windows/Linux) or Cmd + ~ (macOS).

**5.** Run the command `node index.js` to start the server

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/pwvopts5ct2qvkrmo9qc.png)

**6.** Then go to the `http://localhost:3000/`,The message "Hello, World!" is displayed on the webpage.
This is a simple example of creating a server in Node.js using the http module. However, using a framework like Express.js can provide many additional features and make it easier to handle more complex applications.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/y785r2vixxhnzafh1obl.png)



This Blog is just a intro to Node.js and some tools going to be used in order to Create the Online Chat Application, More details will be with my next Blog, Thanks For Reading!