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Node.js Tutorial - Complete Guide from Beginner to Expert

Node.js is a powerful JavaScript runtime environment, built on Google Chrome's V8 JavaScript Engine. Node.js is open-source and cross-platform, widely used by thousands of developers around the world to develop I/O intensive web applications like video streaming sites, single-page applications, and other web applications.

What is Node.js?​

Node.js is not a programming language like Python, Java or C/C++. Node.js is a runtime, similar to Java virtual machine, that converts JavaScript code into machine code.

With Node.js, it is possible to use JavaScript as a backend. With JavaScript already being a popular choice for frontend development, application development around MERN (MongoDB, Express, React and Node.js) and MEAN (MongoDB, Express, Angular and Node.js) stacks is being increasingly employed by developers.

Key Features of Node.js​

  • Single Programming Language: Use JavaScript for both frontend and backend development
  • Asynchronous Execution: Implements asynchronous execution of tasks in a single thread
  • Event-Driven Architecture: Built on event-driven, non-blocking I/O model
  • Cross-Platform: Runs on Windows, Linux, macOS, and other platforms
  • Rich Ecosystem: NPM provides access to millions of packages
  • High Performance: Significantly faster than multi-threaded applications for I/O operations

Why Learn Node.js?​

Node.js can be used to fulfill multiple purposes like server-side programming, building APIs, etc.

  • Server-side Programming: Use JavaScript for backend development
  • Single Language Development: Use JavaScript for both frontend and back-end development
  • Asynchronous Execution: Implements async and await technique for faster applications
  • Versatile Applications: Build command line applications, web applications, real-time chat applications, REST APIs
  • Industry Demand: High demand for Node.js developers in the job market

Applications of Node.js​

Node.js is used for building different types of applications:

Streaming Applications​

Node.js can easily handle real-time data streams, where it is required to download resources on-demand without overloading the server or the user's local machine. Node.js can also provide quick data synchronization between the server and the client.

Single Page Applications (SPAs)​

Node.js is an excellent choice for SPAs because of its capability to efficiently handle asynchronous calls and heavy input/output (I/O) workloads. Data-driven SPAs built with Express.js are fast, efficient and robust.

Real-time Applications​

Node.js is ideal for building lightweight real-time applications, like messaging apps interfaces, chatbots, etc. Node.js has an event-based architecture with excellent WebSocket support, facilitating real-time two-way communication.

APIs​

At the heart of Node.js is JavaScript, making JSON data handling easier. You can build REST-based APIs with Node.js efficiently.

Example of Node.js Application​

Hello World Console Application​

To create a basic Hello World application in Node.js, save the following single line JavaScript as hello.js file:

console.log("Hello World");

Open a terminal in the folder where hello.js file is present, and enter the following command:

node hello.js

Output:

Hello World

Hello World Web Application​

To create a "Hello, World!" web application using Node.js, save the following code as hello-web.js:

const http = require('http');

const listener = function (request, response) {
  // Send the HTTP header
  // HTTP Status: 200 : OK
  // Content Type: text/html
  response.writeHead(200, {'Content-Type': 'text/html'});

  // Send the response body as "Hello World"
  response.end('<h2 style="text-align: center;">Hello World</h2>');
};

const server = http.createServer(listener);
server.listen(3000);

// Console will print the message
console.log('Server running at http://127.0.0.1:3000/');

Run the above script from command line:

node hello-web.js

Output:

Server running at http://127.0.0.1:3000/

The program starts the Node.js server on localhost and goes into listen mode at port 3000. Now open a browser and enter http://127.0.0.1:3000/ as the URL. The browser displays the Hello World message.

Prerequisites to Learn Node.js​

Before proceeding with this tutorial, you should have a basic understanding of JavaScript. As we are going to develop web-based applications using Node.js, it will be good if you have some understanding of other web technologies such as HTML, CSS, AJAX, etc.

Getting Started with Node.js​

This tutorial is designed for software programmers who want to learn Node.js and its architectural concepts from basics to advanced. This tutorial will give you enough understanding on all the necessary components of Node.js with suitable examples.

Tutorial Structure​

This comprehensive Node.js tutorial covers:

Basics of Node.js​

Core Concepts​

Development Tools​

Advanced Topics​

Node.js Jobs and Salary​

Node.js is a popular tool for almost any kind of project. After learning Node.js, you can get jobs in different profiles:

  • Node.js Developer - Salary ranges between $50,000 to $120,000 with an average annual salary of $85,000
  • Node.js Backend Developer - Salary ranges between $60,000 to $130,000 with an average annual salary of $95,000
  • Full-Stack Developer - Salary ranges between $70,000 to $150,000 with an average annual salary of $110,000

Frequently Asked Questions about Node.js​

Is Node.js Free to Use?​

Node.js is an open-source and cross-platform server framework. It is completely free to use on all OS platforms including Windows, Linux, macOS, etc.

Can Node.js be used in commercial applications?​

Certainly. Node.js is being widely used for building commercial applications in the field of streaming apps, SPAs, APIs, etc. Many top companies such as Twitter, Slack, Coursera, Netflix, Uber, and LinkedIn use Node.js in their applications.

Can I deploy Node.js applications on any hosting service?​

Node.js applications can be deployed on popular hosting services such as AWS, Heroku, DigitalOcean, Vercel, Netlify, and more.

Does Node.js support multithreading/concurrency?​

Node.js runtime executes JavaScript in a single thread. It implements asynchronous execution of multiple tasks with async/await mechanism for making non-blocking I/O requests.

How fast is Node.js?​

Compared to languages such as Java, PHP, Python, etc., Node.js offers better performance in terms of speed of execution for I/O-intensive applications. However, for CPU-intensive applications, it may not be as good as C/C++.

Can Node.js be used in AI and machine learning?​

The NPM package manager does have certain packages for machine learning libraries such as TensorFlow.js and Brain.js. However, Python remains the preferred choice for developing AI and machine learning applications.

Next Steps​

Ready to start your Node.js journey? Continue with the next chapters:

  1. Node.js - Introduction - Learn the fundamentals of Node.js
  2. Node.js - Environment Setup - Install and configure Node.js
  3. Node.js - First Application - Create your first Node.js application
  4. Node.js - REPL Terminal - Master the interactive shell
  5. Node.js - Package Manager (NPM) - Learn package management

Ready to become a Node.js expert? Start with the next chapter and build your way up to advanced Node.js development!