Expo

Styled Components is a popular CSS-in-JS library for React and React Native that uses tagged template literals to style components. It automatically generates unique class names, supports dynamic styling based on props, handles vendor prefixing, and provides full theming capabilities. The library colocates styles with components, making it easy to understand what each component looks like and to delete styles safely when removing components.

Turbo Modules are the next-generation native module system in React Native's New Architecture, replacing the traditional bridge-based modules. They use the JavaScript Interface (JSI) for direct, synchronous communication between JavaScript and native code, eliminating the serialization overhead of the old JSON bridge. Turbo Modules also support lazy loading — they're only initialized when first accessed rather than at app startup, which significantly improves launch performance.

Deep linking is the ability to direct users to a specific screen or content within a mobile or web application via a URL, rather than just opening the app's home screen. In React Native and Flutter, this involves configuring URL schemes (e.g., `myapp://profile/123`) or universal/app links that work across platforms. Deep linking is essential for push notification routing, marketing campaigns, sharing content between users, and creating seamless web-to-app transitions.

The React Native New Architecture is a fundamental rewrite of React Native's internals, replacing the asynchronous bridge with a JavaScript Interface (JSI) that enables direct, synchronous communication between JavaScript and native code. It consists of three pillars: Fabric (a new rendering system), Turbo Modules (a faster native module system), and Codegen (automatic type-safe native code generation from JS specs). This architecture significantly improves performance, reduces startup time, and enables concurrent rendering features from React 18.

A WebView is an embeddable browser component that renders web content (HTML, CSS, JavaScript) inside a native mobile application. It allows developers to reuse existing web code within a native app shell, commonly used for displaying rich content, integrating web-based features, or building hybrid apps. While convenient, WebView-heavy apps typically have worse performance and a less native feel compared to truly native or React Native/Flutter approaches.

Tree shaking is a dead code elimination technique used by modern bundlers like Webpack, Rollup, and esbuild to remove unused exports from the final JavaScript bundle. It relies on the static structure of ES module `import`/`export` syntax to determine which code is actually referenced and safely discard the rest. For tree shaking to work effectively, libraries must use ESM format and avoid side effects in their module initialization, which is why the `sideEffects` field in `package.json` matters.