React / React Native
JavaScript library from Meta for interactive web UIs (React) and native mobile apps (React Native) with a shared codebase.
React is the most widely used JavaScript library for building modern user interfaces. Developed by Meta (Facebook), it powers the web frontends of Facebook, Instagram, Netflix and countless other apps. React Native extends the same ideas to native mobile apps for iOS and Android with a shared JavaScript codebase.
What is React / React Native?
React is a declarative JavaScript library for building UIs based on reusable components. Each UI unit (button, form, page) is a component with its own state and render logic. React uses JSX, a syntax extension that embeds HTML in JavaScript. The Virtual DOM efficiently compares changes and updates only the parts of the real DOM that changed. React Native applies this to mobile: instead of HTML elements it renders native UI components (UIView on iOS, Android View), producing real native apps written in JavaScript.
How does React / React Native work?
React components declare what the UI should look like. When state changes, React uses the Virtual DOM to compute the minimal DOM updates (reconciliation) and applies them. Hooks (useState, useEffect, useContext) manage state and side effects in function components. State libraries (Redux, Zustand, Jotai) handle complex app state. Next.js adds server-side rendering, static generation and API routes for production-ready web apps.
Practical Examples
Facebook/Instagram: React powers the feeds, stories and messenger UIs used by billions daily.
Netflix: The streaming UI is built with React, optimised for different devices and fast loading.
E-commerce dashboard: A mid-size retailer uses React with Next.js for its order management system with real-time updates.
Mobile app with React Native: A health-tech startup builds its patient app for iOS and Android with one React Native codebase, saving about 40% dev cost.
Design system: A large company builds a React component library (Storybook) reused across internal web apps.
Typical Use Cases
Single-page applications (SPAs): Interactive web apps with dynamic content and smooth navigation
Cross-platform mobile: One codebase for iOS and Android with React Native
Dashboards and admin panels: Data-heavy UIs with real-time updates
E-commerce frontends: Fast, SEO-friendly shops with Next.js
Design systems: Reusable component libraries for consistent UIs
Advantages and Disadvantages
Advantages
- Large ecosystem: Many libraries, tools and one of the biggest developer communities
- Component-based: Reusable UI building blocks speed development and keep UIs consistent
- Performance: Virtual DOM and React Server Components minimise unnecessary updates
- Cross-platform: React Native gives native iOS and Android apps from shared code
- Hiring: React developers are easier to find thanks to adoption and community
Disadvantages
- Learning curve: JSX, state management, hooks and the ecosystem take time to learn
- View layer only: React is not a full framework; you add libraries for routing, state and data
- Fast evolution: Frequent updates and new concepts (Server Components, Suspense) can overwhelm teams
- Bundle size: Without code splitting and tree-shaking, React apps can become large
Frequently Asked Questions about React / React Native
React or Angular – which is better?
Is React Native worth it vs Flutter?
What is Next.js and do I need it?
Related Terms
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