Introduction to Node.js

JavaScript was originally developed to run in web browsers. However, developers often need to run JavaScript outside of a browser — for example, when building the backend (server-side) of a web application.

To meet this need, we use Node.js, a powerful open-source tool that allows you to run JavaScript in a non-browser environment. Mastering Node.js is essential for any modern JavaScript developer, especially if you're interested in full-stack or backend development.

What is Node.js?

Node.js is a cross-platform JavaScript runtime environment that lets you execute JavaScript code outside the browser. It was designed with server-side development in mind, but it's also used to create desktop tools, command-line utilities, and even Internet of Things (IoT) applications.

By default, JavaScript in the browser cannot interact with the local file system or network beyond web APIs. Node.js extends JavaScript by providing access to the underlying operating system, file system, and network. This makes it ideal for building scalable web servers, real-time applications like chat services, APIs, and other backend services.

Node.js was created in 2009 by software engineer Ryan Dahl. It runs on the V8 engine — the same high-performance JavaScript engine developed by Google for the Chrome browser. V8 compiles JavaScript into fast, low-level machine code that your computer's processor can understand directly.

Node.js logo

Advantages of Node.js

While JavaScript dominates the frontend space, the backend world is full of options — Python, Java, Go, and more. So why choose Node.js? Here are some compelling reasons:

• One language for frontend and backend: With Node.js, you can write both client-side and server-side code in JavaScript. This leads to improved productivity, code reuse, and easier collaboration within development teams.

• Non-blocking I/O and asynchronous architecture: Node.js uses an event-driven, single-threaded model that allows it to handle multiple operations concurrently. This makes it very efficient for I/O-heavy tasks like reading files, making network requests, or handling multiple client connections.

• Vast ecosystem with npm: Node.js comes with npm (Node Package Manager), the largest ecosystem of open-source libraries in the world. It enables you to install, manage, and share packages easily — saving time and reducing bugs by reusing battle-tested code.

• Great for building scalable web services: Node.js is ideal for creating APIs, real-time systems (like messaging apps), and backend services for modern web and mobile apps.

If you're looking to build a full-featured web application without splitting frontend and backend into completely different technologies, Node.js offers a clean and unified development experience.

Installing Node.js

To get started with Node.js, you first need to install it from the official website: nodejs.org

There, you'll find two download options:

• LTS (Long Term Support): A stable version intended for production use. It receives regular updates and security patches.

• Current: A version with the latest features and updates. It's ideal for experimentation or personal projects, but not always recommended for commercial use.

Choose the version appropriate for your needs and download the installer for your operating system (Windows, macOS, or Linux).

Checking the installation

After installation, open your terminal and run:

node --version

or

node -v

If everything went well, you should see the installed version number, for example:

v22.16.0

This confirms that Node.js is successfully installed and ready to use.

Real-world use cases

Node.js is used by some of the world's largest tech companies to power fast, scalable applications. Here are a few examples of how it's used in practice:

• APIs and microservices: Node.js is perfect for building RESTful APIs and microservices due to its non-blocking architecture and lightweight runtime.

• Real-time applications: Messaging apps, live chats, multiplayer games, and collaboration tools (like Google Docs-style editors) benefit from Node.js's event-driven model. For example, Slack and Trello use Node.js for real-time communication features.

• Streaming services: Node.js works well for audio and video streaming services. Netflix, for instance, uses Node.js to handle its high-volume web traffic and improve startup performance.

• Command-line tools and scripts: Many popular developer tools (like ESLint, Prettier, and Webpack) are written in Node.js. It's widely used for automating development workflows.

• Serverless applications: Thanks to its fast startup time and low resource usage, Node.js is often used in serverless environments like AWS Lambda or Google Cloud Functions.

• IoT (Internet of Things): Node.js is lightweight and runs efficiently on small devices, making it a great fit for IoT development.

These examples show how Node.js supports a wide range of applications — from web and mobile services to tools and devices.

When not to use Node.js

While Node.js is powerful and versatile, it's not the best choice for every project. Here are some situations where using Node.js might not be ideal:

• CPU-intensive tasks: Node.js runs on a single thread and is optimized for I/O-bound operations. For applications that require heavy computation (like image processing, video encoding, or machine learning), Node.js can block the event loop, reducing performance.

• Applications with strict type requirements: If you're building a large-scale enterprise app with strict type safety and object-oriented architecture, languages like Java or C# may offer better tooling, performance, and maintainability.

• Real-time rendering or graphics-heavy applications: Node.js is not suitable for tasks like 3D rendering or applications that demand real-time graphical performance, which are better handled by languages like C++ or specialized engines.

• Applications that require multithreading: Although Node.js has a worker thread module, it's still not as straightforward as multithreaded programming in Java or C++. If your app must take full advantage of multiple CPU cores, other languages might serve better.

Always consider your application's specific needs before choosing a backend technology.

Conclusion

In this topic, you learned what Node.js is, why it's useful, how it works, and how to install it. With Node.js, you can build fast and scalable applications using JavaScript on the server side.

You're now ready to begin exploring more advanced Node.js features and start building your own backend applications. Good luck!