Coding Challenges

150 hands-on challenges across 7 categories

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React Native

0/53 completed

React

0/15 completed

JS ES5

0/28 completed

JS ES6+

0/22 completed

Engineering Practices

0/17 completed

Dev Processes

0/6 completed

Extra

0/9 completed

easyReact Native

useState counter with validation

easyReact Native

useEffect cleanup

easyReact Native

FlatList with pull-to-refresh

easyReact Native

TextInput controlled form

mediumReact Native

useReducer for complex state

mediumReact Native

React Navigation stack setup

mediumReact Native

Tab navigator with badges

hardReact Native

Navigation deep link handling

mediumReact Native

Navigation params typing

mediumReact Native

Screen focus listener

easyReact Native

useContext theme provider

mediumReact Native

Zustand store with persist

mediumReact Native

Redux Toolkit slice

mediumReact Native

React Query fetch and cache

hardReact Native

Optimistic updates with React Query

mediumReact Native

React.memo and useMemo

mediumReact Native

FlatList performance optimization

mediumReact Native

Image caching and preloading

easyReact Native

Memoize callbacks with useCallback

hardReact Native

InteractionManager for heavy ops

mediumReact Native

Camera roll permission request

mediumReact Native

expo-notifications local notification

easyReact Native

Native module bridge (Platform.select)

easyReact Native

Linking.openURL deep link

mediumReact Native

Accelerometer sensor subscription

easyReact Native

Flexbox layout: centered card

easyReact Native

Dynamic Styles with useWindowDimensions

easyReact Native

SafeAreaView for notched devices

easyReact Native

Shadow and elevation styles

easyReact Native

StyleSheet.create pattern

mediumReact Native

AsyncStorage CRUD

mediumReact Native

SQLite database setup (expo-sqlite)

mediumReact Native

File system read/write (expo-file-system)

easyReact Native

NetInfo connectivity check

easyReact Native

Clipboard copy/paste

mediumReact Native

Animated.Value fade-in

hardReact Native

Animated event with PanResponder

mediumReact Native

LayoutAnimation for list insert

Conditional rendering

List rendering with keys

Composition vs inheritance

Higher-Order Component pattern

Custom useDebounce hook

Custom useLocalStorage hook

useRef for DOM access

Error boundary component

Profiling with React.memo

Virtualization with react-window

Suspense with React.lazy

useTransition for pending state

Closure counter factory

Module pattern (IIFE)

Function.prototype.bind

Call and apply

Hoisting behavior

Constructor function and new

Prototype chain lookup

hasOwnProperty vs in

Array.map manually

Array.filter manually

Array.reduce manually

typeof vs instanceof

Promise chain

Promise.all for parallel requests

Async/await error handling

Async generator with for-await-of

Destructuring and default params

Spread and rest operators

Arrow functions and lexical this

Map, filter, reduce chaining

easyEngineering Practices

Jest test — describe/it/expect

mediumEngineering Practices

Testing async code

mediumEngineering Practices

Mock functions with Jest

mediumEngineering Practices

Testing React Native components

mediumEngineering Practices

Snapshot testing

easyEngineering Practices

Test coverage thresholds

easyEngineering Practices

Console.log debugging pattern

mediumEngineering Practices

React DevTools profiler

mediumEngineering Practices

Flipper network inspector

mediumEngineering Practices

Error logging service

mediumEngineering Practices

React Native performance monitor

mediumEngineering Practices

DRY — extract reusable hook

mediumEngineering Practices

Single Responsibility: component splitting

hardEngineering Practices

Custom ESLint rule idea

hardEngineering Practices

Git bisect scenario

easyEngineering Practices

Code review checklist

mediumDev Processes

EAS Build workflow

mediumDev Processes

EAS Update channel strategy

hardDev Processes

CI/CD with GitHub Actions for RN

mediumDev Processes

Code review simulation

easyDev Processes

Agile estimation (story points)

TypeScript generics — identity function

TypeScript unions and narrowing

React Native accessibility

i18n with expo-localization

GraphQL query with Apollo Client

WebSocket connection hook

Gesture handler swipeable row

Reanimated shared value animation

End-to-end test with Detox

Isograma (no repeated letters)

Letras por números (alphabet index)

String ends with (no built-in)

Elementos pares (even-count elements)

Transformador (restructure object)

Ceros al final (move zeros)

Validar paréntesis (balanced)

Encontrar al impar (odd count)

Gira sarbalap (reverse long words)

Marquesina (marquee rotation)

Ordenar emociones (sort emoticons)

Contar duplicados (count dupes)

Contar lenguajes (count languages)

Encontrar al aislado (find outlier)

LIS (longest increasing subsequence)

Urinales libres (free urinals)

Carrito (shopping cart function)

Palabrador (word overlapping)

Anagramas (anagram check)

Conteo de caracteres

Duplicados en array

Suma de rangos

Números perdidos (missing numbers)

Es letra (is single letter)

Palíndromos (rearrange to palindrome)

mediumReact Native

User Directory with FlatList

mediumReact Native

Product Search with Filters

mediumReact Native

Grocery List (CRUD with persistence)

mediumReact Native

Pokemon Store (cart with limits)

mediumReact Native

Shopping Cart with Context

hardReact Native

Wordle (word guessing game)

hardReact Native

Minesweeper Grid (Booscaminas)

mediumReact Native

Tic-Tac-Toe (Ta-Te-Ti)

mediumReact Native

Symmetrical Grid (Grilla Simétrica)

mediumReact Native

Word Guessing Game (Adivinar Pokemon)

mediumReact Native

Reaction Game (Juego de Reflejos)

mediumReact Native

Stroop Color Game (Juego de Colores)

hardReact Native

G-Counter CRDT for offline sync

Debounce with leading edge and cancel

Predict the event-loop order

deepEqual from scratch

LRU cache with Map

curry and compose

Undo/redo reducer

Normalized entities reducer

createSelector with memoization

mediumReact Native

FlatList windowing math

mediumReact Native

Worklet-style interpolate and clamp

mediumEngineering Practices

Exponential backoff with jitter

mediumDev Processes

OTA update gate (runtimeVersion)