2.8a Front-End Development

API communication: Different architecture standards (REST, GraphQL), data formats (JSON, XML), request lifecycle.
DOM: The Document Object Model—the browser's programmatic representation of an HTML document as a node tree. Virtual DOM is a lightweight in-memory representation maintained by frameworks like React; it minimizes real DOM operations via diffing algorithms.
Browser events: Capturing and bubbling phases, event delegation, custom events.
Responsive design: Purpose, advantages, progressive enhancement. Media queries, flexible layouts (flexbox/grid), and relative units (rem/vw) adapt interfaces to different screen sizes.
Client-side rendering (CSR) vs. server-side rendering (SSR):
CSR: Browser downloads JS bundle and renders locally. Slow first paint, poor SEO, but smooth interaction.
SSR: Server generates full HTML response. Fast first paint, good SEO, but higher server load.
Hybrid approaches (SSG / ISR): Pre-render at build time or incrementally regenerate static pages.
Pagination: Offset-based, cursor-based, infinite scroll.
State management: Consistency problems with shared state across components. Solutions: Prop Drilling → Context → Redux / Zustand / Pinia.
MVC and derivatives: MVP, MVVM—architectural patterns separating view logic, business logic, and data models.
WebSocket: Full-duplex communication protocol for real-time applications (chat, collaborative editing, live data push).