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Overview

React Basics

All React Basics

What is the Virtual DOM?

What is reconciliation in React?

What is JSX?

What is the difference between props and state?

What causes a React component to re-render?

What are keys and why are they important?

What is a controlled component?

What is an uncontrolled component?

What is React Strict Mode?

Hooks

All Hooks

Explain the useEffect Hook

Explain the `useState` Hook.

Explain the `useEffect` Hook.

What is the difference between `useEffect` and `useLayoutEffect`?

When should you use `useMemo`?

When should you use `useCallback`?

What is `useRef` used for?

How do you build a custom Hook?

How do stale closures happen in Hooks?

How do you avoid an infinite effect loop?

State Management

All State Management

Where should state live in a React application?

What is lifting state up?

What is derived state and why should you avoid storing it?

How do you update nested state immutably?

What is state colocation?

When is Context appropriate for state?

When should you use a client-state library?

How do you model async request state?

What is optimistic UI?

How do you prevent race conditions in state updates?

Performance Optimization

All Performance Optimization

How do you diagnose unnecessary React re-renders?

What does `React.memo` do?

What are the limits of `useMemo` and `useCallback`?

How do you virtualize a large list?

What is code splitting with `lazy` and `Suspense`?

How do you optimize Context consumers?

How do stable keys improve rendering?

What is concurrent rendering?

How do you optimize expensive calculations?

How do you profile a React app?

React Router

All React Router

What is client-side routing?

How do nested routes work in React Router?

What is an outlet?

How do route parameters work?

How do you protect a route?

How do you navigate programmatically?

What are loaders and actions?

How do you handle a 404 route?

How do you preserve query parameters?

How do you split route bundles?

Context API

All Context API

What problem does the Context API solve?

How do you create and consume Context?

How does Context affect re-renders?

How do you avoid Context performance problems?

When should Context not replace a state manager?

How do you test a component that consumes Context?

How do you compose multiple providers?

How do you give Context a safe default?

How do you update Context from a child?

How do you split a large Context?

Redux

All Redux

What are the core Redux principles?

What are actions, reducers, and the store?

Why must Redux reducers be pure?

What is Redux Toolkit?

What is a selector?

How do you handle async logic with Redux?

What is middleware?

What is normalized state?

How do you avoid unnecessary Redux re-renders?

When is Redux not a good fit?

Advanced React

All Advanced React

What are error boundaries?

What are portals?

What is a render prop?

What is a higher-order component?

What are compound components?

What is `forwardRef`?

What is `useImperativeHandle`?

What is hydration?

What is server-side rendering?

What is React Server Components?

React Architecture

All React Architecture

How do you organize a scalable React project?

How do you separate presentational and container concerns?

How do you design reusable components?

How do you handle feature flags?

How do you define API boundaries in React?

How do you make React code testable?

How do you manage forms at scale?

How do you handle global errors?

How do you design a design-system component?

How do you migrate a legacy React application?

React Coding Challenges

All React Coding Challenges

Build a searchable, sortable React list.

Build a debounced search input.

Build a reusable modal component.

Build a paginated data table.

Build a multi-step form.

Build a toast notification system.

Build a custom `useFetch` Hook.

Build a virtualized list.

Build an accessible tabs component.

Build an optimistic todo list.

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React Basics

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