A JavaScript library for building user interfaces.
React.js is one of the most widely adopted open-source JavaScript libraries, developed by Meta (formerly Facebook), for building fast, dynamic, and user-friendly applications. It enables developers to create reusable components, ensuring modularity and scalability across projects of any size. React uses a **virtual DOM** to efficiently update only the required parts of the UI, resulting in high performance even in complex applications. Its **component-based architecture** allows developers to encapsulate logic, styling, and layout within self-contained units, making development faster and easier to maintain. ### Key Features: - **JSX (JavaScript XML):** A declarative syntax that combines HTML with JavaScript for writing clean, intuitive UI components. - **Hooks:** Built-in functions like useState, useEffect, and useContext for managing state and side effects in functional components. - **Context API:** Simplifies state sharing across multiple components without excessive prop drilling. - **Declarative UI:** Developers describe how the UI should look, and React automatically updates it when the underlying data changes. - **Rich Ecosystem:** Compatible with tools and frameworks like Next.js, Redux Toolkit, React Query, and Tailwind CSS. - **Strong Community:** Supported by a massive developer base, frequent updates, and a wide range of third-party libraries. ### Why Choose React: - **Performance:** Virtual DOM and efficient reconciliation deliver smooth rendering and fast updates. - **Scalability:** Ideal for small apps to enterprise-level solutions. - **SEO-Friendly:** Paired with Next.js, React supports server-side rendering (SSR) and static site generation (SSG). - **Future-Proof:** Backed by Meta and a vibrant open-source community, ensuring long-term support. ### Common Use Cases: - Single Page Applications (SPAs) - Enterprise Dashboards and Portals - E-commerce Platforms - Social Media and Real-Time Apps - Blogs, Marketing Sites, and SEO-optimized Platforms ### Sample Code: ```tsx import { useState } from "react"; export default function Counter() { const [count, setCount] = useState(0); return ( <button onClick={() => setCount(c => c + 1)}> Clicked {count} times </button> ); } ``` ### Best Practices: - Keep components small, reusable, and maintainable. - Use Hooks to manage state and side effects efficiently. - Implement code-splitting and lazy loading for performance. - Leverage TypeScript for type safety and cleaner code. - Write tests with React Testing Library and Jest. React is trusted by companies like Facebook, Netflix, Airbnb, and Instagram, making it a reliable choice for any modern web project. Official Website: https://react.dev