React & TypeScript Challenges
Master React hooks, rendering behavior, TypeScript patterns, and performance optimization. Solution unlocks after 10 attempts.
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Pick a topic and learn in order, or jump to the flat list to see everything.
18 challenges Hooks Fundamentals
useState, useReducer, useRef, closures and the rules of hooks.
0/18- MediumThe Stale Closure Trap
- EasySynchronous State Updates?
- EasyThe Conditional Hook (The Illegal Move)
14 challenges Effects & Async
useEffect mechanics, race conditions, cleanup, hydration and data fetching.
0/14- MediumDependency Array Lying
- MediumuseLayoutEffect vs useEffect
- HardRace Conditions in useEffect
12 challenges Performance & Memoization
memo, useMemo, useCallback, context splitting and re-render prevention.
0/12- MediumContext & Unnecessary Re-renders
- MediumReact.memo & Callback Props
- MediumReducing Re-renders via Composition
10 challenges Concurrent React 18 / 19
Suspense, useTransition, useDeferredValue, lazy loading and the use() hook.
0/10- HardConcurrent Rendering with useTransition
- HardSuspense with Error Boundaries
- HarduseDeferredValue for Search
3 challenges Server Components & Boundaries
'use client' placement, the serialization wall and the children-slot pattern.
0/3- MediumPush 'use client' to the Leaf
- HardThe Serialization Wall: RSC Props
- MediumClient Shell, Server Children: the Slot Pattern
6 challenges Refs & Imperative APIs
forwardRef, useImperativeHandle, useId, click-outside and ref typing.
0/6- MediumTyping forwardRef
- HardRef Forwarding Chain
- HarduseImperativeHandle for Custom Ref API
13 challenges Component Patterns
Compound components, HOCs, render props, polymorphic types and error boundaries.
0/13- HardPolymorphic Components with TS
- HardSynthetic Events vs Native
- EasyComponent Definition inside Render
9 challenges Forms & Inputs
Controlled inputs, validation, useActionState, debounce and accessible forms.
0/9- MediumControlled vs Uncontrolled Components
- HardOptimistic UI Updates
- MediumControlled Form with Real-time Validation
13 challenges UI Patterns
Portals, modals, focus traps, infinite scroll, drag-drop and virtualization.
0/13- HardPortal with Event Handling
- MediumPortal for Modal Overlay
- MediumInfinite Scroll with IntersectionObserver