Quick recall
Higher-order components wrap behavior, while controlled and uncontrolled components describe where important state lives.
Before hooks, HOCs and render props were common ways to share stateful logic across components.
Hooks let function components use stateful and lifecycle-like logic without classes, but they have strict usage rules.
JSX is a syntax extension that lets React developers describe UI trees inside JavaScript more readably.
JSX has a few important rules around single roots, expressions, fragments, and rendering arrays of elements.
React uses keys to identify list items across renders so reconciliation can preserve identity correctly.
The must-know React interview set revolves around React basics, JSX, props, state, hooks, keys, reconciliation, Context, Redux, routing, data fetching, lazy loading, Suspense, error boundaries, StrictMode, SSR vs CSR, hydration, and performance.
Next.js builds on React by adding routing, rendering strategies, data-loading patterns, and production-focused conventions.
Initial render and later re-renders follow different triggers, and where state lives strongly affects how much of the tree must update.
React props can carry values, callbacks, children, and even JSX, but deep prop chains can become hard to manage.
Props are read-only inputs from a parent, while state is data the component manages and can change over time.
React architecture questions test how you organize real applications rather than isolated component syntax.