Learn React
React questions here focus on how rendering actually works: state, effects, keys and derived data, rather than memorising API names.
Written against React 18/19 function components.
What you will practise
- Props, state and rendering
- Hooks and their rules
- Effects and dependencies
- Lists, keys and derived state
Roadmap
Work through the levels in order, or jump to where you are.
React quizzes
Interactive React challenges
Hands-on activities: find bugs, complete code, order steps and match concepts.
React articles
React Interview Questions Explained: Core Concepts with Clear Answers
Ten common React interview topics explained in depth, from reconciliation and keys to effects and memoisation, so you can answer in your own words instead of memorising.
A Mental Model for React Hooks
Why hooks behave the way they do: renders as snapshots, effects as synchronisation, and how that explains stale closures and infinite loops.
React Props vs State: What Is the Difference and When to Use Each
A clear explanation of props and state in React, how data flows between components, when to lift state up and how to avoid duplicating state.
FAQ
Which React version is covered?
React 18 and 19 function components and hooks. Class components are not covered.
Do I need to know Next.js to take these quizzes?
No. These quizzes focus purely on the React library itself, not on meta-frameworks.
What is the most common mistake students make in React?
Misunderstanding the dependency array in useEffect, and mutating state directly. Our intermediate quizzes test both extensively.
Do you cover state management libraries like Redux or Zustand?
Not yet. The current roadmap focuses entirely on built-in React state (useState, useReducer, and Context).