React: JavaScript library for efficient UI development. Virtual DOM, components, props, and state management. Easy setup, reusable code, and vast ecosystem. Encourages modular thinking and collaboration. Powerful features for dynamic interfaces.

JSX blends JavaScript and HTML for intuitive UI components in React. It offers cleaner syntax, JavaScript integration, and component-based architecture. JSX enables dynamic rendering, conditional logic, and reusable elements, enhancing UI development flexibility and efficiency.

React functional components: reusable, self-contained UI building blocks. Simpler than class components. Use hooks for state and effects. Encourage pure functions, composability, and separation of concerns. Easy to test and maintain.

React props: data messengers between components. Immutable, versatile, enable reusable UI. Key to data flow, conditional rendering, and component communication. Essential for building efficient, maintainable React applications.

useState simplifies state management in React functional components. It allows easy state tracking and updates, improving code clarity and organization. Multiple states can be managed independently within a single component.

React's event handling system simplifies user interactions. It uses synthetic events for cross-browser consistency, supports event delegation for performance, and allows easy integration of custom logic through JSX.

Conditional rendering in React displays different UI elements based on conditions, using techniques like ternary operators, && operator, and if-else statements. It enables dynamic, personalized interfaces and improves user experience.

React's map function transforms arrays into UI elements. Keys uniquely identify list items, optimizing rendering and tracking changes. Use unique IDs as keys for better performance and stability.

React simplifies form creation, using controlled components for state management. Handles multiple inputs, dropdowns, checkboxes, and radio buttons. Supports custom validation and asynchronous submission. Enhances user interaction and data handling in web applications.

Lifting state up centralizes shared data management in higher-level components, enhancing data flow, component synchronization, and maintaining a single source of truth. It promotes reusability and simplifies complex application development.

React component lifecycle methods control component behavior from birth to death. They enable optimized rendering, data fetching, and cleanup. Hooks like useEffect provide similar functionality in functional components.

React's useEffect hook manages side effects in functional components, handling tasks like data fetching, DOM manipulation, and subscriptions. It runs after rendering, allowing synchronization with external systems and async operations.

React Router enables client-side routing in React apps, offering seamless navigation without page reloads. It provides components for defining routes, creating links, and handling dynamic paths, enhancing user experience and app performance.

React fragments group elements without extra DOM nodes, improving component structure and layout flexibility. They're lightweight, support keys, and work well with conditional rendering and lists.

Higher-Order Components (HOCs) in React enhance component functionality by wrapping them. They promote code reuse, handle cross-cutting concerns, and add features like data fetching and authentication to components without modifying their core logic.

React's ref attribute enables direct DOM manipulation, allowing precise control over elements. It's useful for focus management, text selection, and animations. Refs provide a way to interact with DOM elements without triggering re-renders, making them versatile for various UI tasks.

PropTypes and DefaultProps enhance React component reliability. PropTypes validate prop types, catching errors early. DefaultProps provide fallback values. Together, they improve code robustness, maintainability, and serve as component documentation.

React Dev Tools: Browser extension for debugging React apps. Shows component tree, props, state, and hooks. Enables real-time editing, performance profiling, and component search. Essential for efficient React development and optimization.

React data fetching: useState for state, useEffect for API calls. Handle loading/errors. Use Fetch or Axios. Implement async/await, cleanup functions. Create custom hooks for reusability. Always sanitize data.

React deployment: optimize with production build, use platforms like Netlify or Vercel, set environment variables, implement routing, focus on performance, automate deployment, and consider advanced strategies for complex apps.