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React and Next.js Patterns

Name: React and Next.js Patterns
Author: affaan-m

Your AI applies modern frontend patterns for React and Next.js components, state management, data fetching, and performance. It supports composition, memoization, routing, forms, and accessible responsive UI best practices.

affaan-m on GitHub

Curated by PromptsEdge from a public repo · MIT license. All credit goes to the author.

What is this skill?

Modern frontend patterns for React, Next.js, and performant user interfaces.

When to use

Building React components (composition, props, rendering)
Managing state (useState, useReducer, Zustand, Context)
Implementing data fetching (SWR, React Query, server components)
Optimizing performance (memoization, virtualization, code splitting)
Working with forms (validation, controlled inputs, Zod schemas)
Handling client-side routing and navigation
Building accessible, responsive UI patterns

Component Patterns

Composition Over Inheritance

typescript

// PASS: GOOD: Component composition
interface CardProps {
  children: React.ReactNode
  variant?: 'default' | 'outlined'
}

export function Card({ children, variant = 'default' }: CardProps) {
  return <div className={`card card-${variant}`}>{children}</div>
}

export function CardHeader({ children }: { children: React.ReactNode }) {
  return <div className="card-header">{children}</div>
}

export function CardBody({ children }: { children: React.ReactNode }) {
  return <div className="card-body">{children}</div>
}

// Usage
<Card>
  <CardHeader>Title</CardHeader>
  <CardBody>Content</CardBody>
</Card>

Compound Components

typescript

interface TabsContextValue {
  activeTab: string
  setActiveTab: (tab: string) => void
}

const TabsContext = createContext<TabsContextValue | undefined>(undefined)

export function Tabs({ children, defaultTab }: {
  children: React.ReactNode
  defaultTab: string
}) {
  const [activeTab, setActiveTab] = useState(defaultTab)

  return (
    <TabsContext.Provider value={{ activeTab, setActiveTab }}>
      {children}
    </TabsContext.Provider>
  )
}

export function TabList({ children }: { children: React.ReactNode }) {
  return <div className="tab-list">{children}</div>
}

export function Tab({ id, children }: { id: string, children: React.ReactNode }) {
  const context = useContext(TabsContext)
  if (!context) throw new Error('Tab must be used within Tabs')

  return (
    <button
      className={context.activeTab === id ? 'active' : ''}
      onClick={() => context.setActiveTab(id)}
    >
      {children}
    </button>
  )
}

// Usage
<Tabs defaultTab="overview">
  <TabList>
    <Tab id="overview">Overview</Tab>
    <Tab id="details">Details</Tab>
  </TabList>
</Tabs>

Render Props Pattern

typescript

interface DataLoaderProps<T> {
  url: string
  children: (data: T | null, loading: boolean, error: Error | null) => React.ReactNode
}

export function DataLoader<T>({ url, children }: DataLoaderProps<T>) {
  const [data, setData] = useState<T | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<Error | null>(null)

  useEffect(() => {
    fetch(url)
      .then(res => res.json())
      .then(setData)
      .catch(setError)
      .finally(() => setLoading(false))
  }, [url])

  return <>{children(data, loading, error)}</>
}

// Usage
<DataLoader<Market[]> url="/api/markets">
  {(markets, loading, error) => {
    if (loading) return <Spinner />
    if (error) return <Error error={error} />
    return <MarketList markets={markets!} />
  }}
</DataLoader>

Custom Hooks Patterns

State Management Hook

typescript

export function useToggle(initialValue = false): [boolean, () => void] {
  const [value, setValue] = useState(initialValue)

  const toggle = useCallback(() => {
    setValue(v => !v)
  }, [])

  return [value, toggle]
}

// Usage
const [isOpen, toggleOpen] = useToggle()

Async Data Fetching Hook

typescript

interface UseQueryOptions<T> {
  onSuccess?: (data: T) => void
  onError?: (error: Error) => void
  enabled?: boolean
}

export function useQuery<T>(
  key: string,
  fetcher: () => Promise<T>,
  options?: UseQueryOptions<T>
) {
  const [data, setData] = useState<T | null>(null)
  const [error, setError] = useState<Error | null>(null)
  const [loading, setLoading] = useState(false)

  // Keep the latest fetcher/options in refs so refetch stays referentially
  // stable even when callers pass inline functions and object literals.
  // Without this, every render creates a new refetch, and the effect below
  // re-runs after each state update - an infinite fetch loop.
  const fetcherRef = useRef(fetcher)
  const optionsRef = useRef(options)
  useEffect(() => {
    fetcherRef.current = fetcher
    optionsRef.current = options
  })

  const refetch = useCallback(async () => {
    setLoading(true)
    setError(null)

    try {
      const result = await fetcherRef.current()
      setData(result)
      optionsRef.current?.onSuccess?.(result)
    } catch (err) {
      const error = err as Error
      setError(error)
      optionsRef.current?.onError?.(error)
    } finally {
      setLoading(false)
    }
  }, [])

  const enabled = options?.enabled !== false

  useEffect(() => {
    if (enabled) {
      refetch()
    }
  }, [key, enabled, refetch])

  return { data, error, loading, refetch }
}

// Usage
const { data: markets, loading, error, refetch } = useQuery(
  'markets',
  () => fetch('/api/markets').then(r => r.json()),
  {
    onSuccess: data => console.log('Fetched', data.length, 'markets'),
    onError: err => console.error('Failed:', err)
  }
)

Debounce Hook

typescript

export function useDebounce<T>(value: T, delay: number): T {
  const [debouncedValue, setDebouncedValue] = useState<T>(value)

  useEffect(() => {
    const handler = setTimeout(() => {
      setDebouncedValue(value)
    }, delay)

    return () => clearTimeout(handler)
  }, [value, delay])

  return debouncedValue
}

// Usage
const [searchQuery, setSearchQuery] = useState('')
const debouncedQuery = useDebounce(searchQuery, 500)

useEffect(() => {
  if (debouncedQuery) {
    performSearch(debouncedQuery)
  }
}, [debouncedQuery])

State Management Patterns

Context + Reducer Pattern

typescript

interface State {
  markets: Market[]
  selectedMarket: Market | null
  loading: boolean
}

type Action =
  | { type: 'SET_MARKETS'; payload: Market[] }
  | { type: 'SELECT_MARKET'; payload: Market }
  | { type: 'SET_LOADING'; payload: boolean }

function reducer(state: State, action: Action): State {
  switch (action.type) {
    case 'SET_MARKETS':
      return { ...state, markets: action.payload }
    case 'SELECT_MARKET':
      return { ...state, selectedMarket: action.payload }
    case 'SET_LOADING':
      return { ...state, loading: action.payload }
    default:
      return state
  }
}

const MarketContext = createContext<{
  state: State
  dispatch: Dispatch<Action>
} | undefined>(undefined)

export function MarketProvider({ children }: { children: React.ReactNode }) {
  const [state, dispatch] = useReducer(reducer, {
    markets: [],
    selectedMarket: null,
    loading: false
  })

  return (
    <MarketContext.Provider value={{ state, dispatch }}>
      {children}
    </MarketContext.Provider>
  )
}

export function useMarkets() {
  const context = useContext(MarketContext)
  if (!context) throw new Error('useMarkets must be used within MarketProvider')
  return context
}

Performance Optimization

Memoization

typescript

// PASS: useMemo for expensive computations
// Copy before sorting - Array.prototype.sort mutates in place
const sortedMarkets = useMemo(() => {
  return [...markets].sort((a, b) => b.volume - a.volume)
}, [markets])

// PASS: useCallback for functions passed to children
const handleSearch = useCallback((query: string) => {
  setSearchQuery(query)
}, [])

// PASS: React.memo for pure components
export const MarketCard = React.memo<MarketCardProps>(({ market }) => {
  return (
    <div className="market-card">
      <h3>{market.name}</h3>
      <p>{market.description}</p>
    </div>
  )
})

Code Splitting & Lazy Loading

typescript

import { lazy, Suspense } from 'react'

// PASS: Lazy load heavy components
const HeavyChart = lazy(() => import('./HeavyChart'))
const ThreeJsBackground = lazy(() => import('./ThreeJsBackground'))

export function Dashboard() {
  return (
    <div>
      <Suspense fallback={<ChartSkeleton />}>
        <HeavyChart data={data} />
      </Suspense>

      <Suspense fallback={null}>
        <ThreeJsBackground />
      </Suspense>
    </div>
  )
}

Virtualization for Long Lists

typescript

import { useVirtualizer } from '@tanstack/react-virtual'

export function VirtualMarketList({ markets }: { markets: Market[] }) {
  const parentRef = useRef<HTMLDivElement>(null)

  const virtualizer = useVirtualizer({
    count: markets.length,
    getScrollElement: () => parentRef.current,
    estimateSize: () => 100,  // Estimated row height
    overscan: 5  // Extra items to render
  })

  return (
    <div ref={parentRef} style={{ height: '600px', overflow: 'auto' }}>
      <div
        style={{
          height: `${virtualizer.getTotalSize()}px`,
          position: 'relative'
        }}
      >
        {virtualizer.getVirtualItems().map(virtualRow => (
          <div
            key={virtualRow.index}
            style={{
              position: 'absolute',
              top: 0,
              left: 0,
              width: '100%',
              height: `${virtualRow.size}px`,
              transform: `translateY(${virtualRow.start}px)`
            }}
          >
            <MarketCard market={markets[virtualRow.index]} />
          </div>
        ))}
      </div>
    </div>
  )
}

Form Handling Patterns

Controlled Form with Validation

typescript

interface FormData {
  name: string
  description: string
  endDate: string
}

interface FormErrors {
  name?: string
  description?: string
  endDate?: string
}

export function CreateMarketForm() {
  const [formData, setFormData] = useState<FormData>({
    name: '',
    description: '',
    endDate: ''
  })

  const [errors, setErrors] = useState<FormErrors>({})

  const validate = (): boolean => {
    const newErrors: FormErrors = {}

    if (!formData.name.trim()) {
      newErrors.name = 'Name is required'
    } else if (formData.name.length > 200) {
      newErrors.name = 'Name must be under 200 characters'
    }

    if (!formData.description.trim()) {
      newErrors.description = 'Description is required'
    }

    if (!formData.endDate) {
      newErrors.endDate = 'End date is required'
    }

    setErrors(newErrors)
    return Object.keys(newErrors).length === 0
  }

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault()

    if (!validate()) return

    try {
      await createMarket(formData)
      // Success handling
    } catch (error) {
      // Error handling
    }
  }

  return (
    <form onSubmit={handleSubmit}>
      <input
        value={formData.name}
        onChange={e => setFormData(prev => ({ ...prev, name: e.target.value }))}
        placeholder="Market name"
      />
      {errors.name && <span className="error">{errors.name}</span>}

      {/* Other fields */}

      <button type="submit">Create Market</button>
    </form>
  )
}

Error Boundary Pattern

typescript

interface ErrorBoundaryState {
  hasError: boolean
  error: Error | null
}

export class ErrorBoundary extends React.Component<
  { children: React.ReactNode },
  ErrorBoundaryState
> {
  state: ErrorBoundaryState = {
    hasError: false,
    error: null
  }

  static getDerivedStateFromError(error: Error): ErrorBoundaryState {
    return { hasError: true, error }
  }

  componentDidCatch(error: Error, errorInfo: React.ErrorInfo) {
    console.error('Error boundary caught:', error, errorInfo)
  }

  render() {
    if (this.state.hasError) {
      return (
        <div className="error-fallback">
          <h2>Something went wrong</h2>
          <p>{this.state.error?.message}</p>
          <button onClick={() => this.setState({ hasError: false })}>
            Try again
          </button>
        </div>
      )
    }

    return this.props.children
  }
}

// Usage
<ErrorBoundary>
  <App />
</ErrorBoundary>

Animation Patterns

Framer Motion Animations

typescript

import { motion, AnimatePresence } from 'framer-motion'

// PASS: List animations
export function AnimatedMarketList({ markets }: { markets: Market[] }) {
  return (
    <AnimatePresence>
      {markets.map(market => (
        <motion.div
          key={market.id}
          initial={{ opacity: 0, y: 20 }}
          animate={{ opacity: 1, y: 0 }}
          exit={{ opacity: 0, y: -20 }}
          transition={{ duration: 0.3 }}
        >
          <MarketCard market={market} />
        </motion.div>
      ))}
    </AnimatePresence>
  )
}

// PASS: Modal animations
export function Modal({ isOpen, onClose, children }: ModalProps) {
  return (
    <AnimatePresence>
      {isOpen && (
        <>
          <motion.div
            className="modal-overlay"
            initial={{ opacity: 0 }}
            animate={{ opacity: 1 }}
            exit={{ opacity: 0 }}
            onClick={onClose}
          />
          <motion.div
            className="modal-content"
            initial={{ opacity: 0, scale: 0.9, y: 20 }}
            animate={{ opacity: 1, scale: 1, y: 0 }}
            exit={{ opacity: 0, scale: 0.9, y: 20 }}
          >
            {children}
          </motion.div>
        </>
      )}
    </AnimatePresence>
  )
}

Accessibility Patterns

Keyboard Navigation

typescript

export function Dropdown({ options, onSelect }: DropdownProps) {
  const [isOpen, setIsOpen] = useState(false)
  const [activeIndex, setActiveIndex] = useState(0)

  const handleKeyDown = (e: React.KeyboardEvent) => {
    switch (e.key) {
      case 'ArrowDown':
        e.preventDefault()
        setActiveIndex(i => Math.min(i + 1, options.length - 1))
        break
      case 'ArrowUp':
        e.preventDefault()
        setActiveIndex(i => Math.max(i - 1, 0))
        break
      case 'Enter':
        e.preventDefault()
        onSelect(options[activeIndex])
        setIsOpen(false)
        break
      case 'Escape':
        setIsOpen(false)
        break
    }
  }

  return (
    <div
      role="combobox"
      aria-expanded={isOpen}
      aria-haspopup="listbox"
      onKeyDown={handleKeyDown}
    >
      {/* Dropdown implementation */}
    </div>
  )
}

Focus Management

typescript

export function Modal({ isOpen, onClose, children }: ModalProps) {
  const modalRef = useRef<HTMLDivElement>(null)
  const previousFocusRef = useRef<HTMLElement | null>(null)

  useEffect(() => {
    if (isOpen) {
      // Save currently focused element
      previousFocusRef.current = document.activeElement as HTMLElement

      // Focus modal
      modalRef.current?.focus()
    } else {
      // Restore focus when closing
      previousFocusRef.current?.focus()
    }
  }, [isOpen])

  return isOpen ? (
    <div
      ref={modalRef}
      role="dialog"
      aria-modal="true"
      tabIndex={-1}
      onKeyDown={e => e.key === 'Escape' && onClose()}
    >
      {children}
    </div>
  ) : null
}

Remember: Modern frontend patterns enable maintainable, performant user interfaces. Choose patterns that fit your project complexity.

Install this skill

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Get the skill — it’s free
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2
Download or clone the files
Download the zip, or clone the repo and copy the skills/frontend-patterns folder.
3
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For Claude Code, use your personal skills folder (every project) or a project’s own folder:
```
~/.claude/skills/frontend-patterns/SKILL.md      # all projects
.claude/skills/frontend-patterns/SKILL.md        # this project only
```
4
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SKILL.md frontmatter

What your agent reads to decide when to load this skill.

---
name: frontend-patterns
description: Frontend development patterns for React, Next.js, state management, performance optimization, and UI best practices. Use when building or reviewing React or Next.js components, state, or render performance.
---

Related skills

View all →

What is this skill?

When to use

What’s inside

Component Patterns

Composition Over Inheritance

Compound Components

Render Props Pattern

Custom Hooks Patterns

State Management Hook

Async Data Fetching Hook

Debounce Hook

State Management Patterns

Context + Reducer Pattern

Performance Optimization

Memoization

Code Splitting & Lazy Loading

Virtualization for Long Lists

Form Handling Patterns

Controlled Form with Validation

Error Boundary Pattern

Animation Patterns

Framer Motion Animations

Accessibility Patterns

Keyboard Navigation

Focus Management

Install this skill

SKILL.md frontmatter

Files