ReactJS, commonly referred to as React, is a free and open-source JavaScript library used for building user interfaces, especially single-page applications where a smooth, dynamic user experience is crucial
Developed by Facebook in 2013, React has since become one of the most widely used tools for frontend web development. It allows developers to build reusable UI components, which makes code easier to manage and scale.
At its core, React uses a concept called the Virtual DOM. Instead of directly manipulating the browser’s Document Object Model (DOM), React creates a virtual version of it in memory. When a change occurs, React updates only the necessary parts of the real DOM, resulting in faster and more efficient performance.
One of the biggest advantages of React is its component-based architecture. Everything in React is a component — a modular piece of the UI. This makes it easy to break down complex interfaces into smaller, manageable parts that can be developed and tested independently.
React also introduces a special syntax called JSX (JavaScript XML), which allows developers to write HTML-like code inside JavaScript. While it might look unusual at first, JSX improves code readability and brings markup and logic together in one place.
React isn’t a full-fledged framework — it focuses strictly on the view layer. This means you can pair it with other libraries or tools (like Redux for state management or React Router for routing) to build robust applications.
In short, ReactJS is:
- Declarative: You describe what you want to see, and React handles the rest.
- Component-based: Build encapsulated components that manage their own state.
- Fast: Thanks to the Virtual DOM, React is optimized for performance.
- Backed by a strong community and major companies like Meta (Facebook).
Whether you’re building a portfolio website or a complex dashboard, React offers the flexibility and power to create modern web applications efficiently.