frontend-patterns

Patrones de desarrollo frontend para React, Next.js, gestión de estado, optimización de rendimiento y buenas prácticas de UI.

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Patrones de Desarrollo Frontend

Patrones modernos de frontend para React, Next.js e interfaces de usuario de alto rendimiento.

Cuándo Activar

Construir componentes React (composición, props, renderizado)
Gestionar estado (useState, useReducer, Zustand, Context)
Implementar obtención de datos (SWR, React Query, server components)
Optimizar rendimiento (memoización, virtualización, code splitting)
Trabajar con formularios (validación, inputs controlados, esquemas Zod)
Manejar routing y navegación del lado del cliente
Construir patrones de UI accesibles y responsivos

Patrones de Componentes

Composición sobre Herencia

// PASS: BIEN: Composición de componentes
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>
}

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

Compound Components

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>
  )
}

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

Patrón Render Props

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)}</>
}

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

Patrones de Custom Hooks

Hook de Gestión de Estado

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

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

  return [value, toggle]
}

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

Hook de Obtención de Datos Asíncrona

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)

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

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

  useEffect(() => {
    if (options?.enabled !== false) {
      refetch()
    }
  }, [key, refetch, options?.enabled])

  return { data, error, loading, refetch }
}

// Uso
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)
  }
)

Hook de Debounce

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
}

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

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

Patrones de Gestión de Estado

Patrón Context + Reducer

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
}

Optimización de Rendimiento

Memoización

// PASS: useMemo para cómputos costosos
const sortedMarkets = useMemo(() => {
  return markets.sort((a, b) => b.volume - a.volume)
}, [markets])

// PASS: useCallback para funciones pasadas a hijos
const handleSearch = useCallback((query: string) => {
  setSearchQuery(query)
}, [])

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

Code Splitting y Carga Diferida

import { lazy, Suspense } from 'react'

// PASS: Carga diferida de componentes pesados
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>
  )
}

Virtualización para Listas Largas

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,  // Altura estimada de fila
    overscan: 5  // Elementos extra a renderizar
  })

  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>
  )
}

Patrones de Manejo de Formularios

Formulario Controlado con Validación

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)
      // Manejo de éxito
    } catch (error) {
      // Manejo de error
    }
  }

  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>}

      {/* Otros campos */}

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

Patrón Error Boundary

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
  }
}

// Uso
<ErrorBoundary>
  <App />
</ErrorBoundary>

Patrones de Animación

Animaciones con Framer Motion

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

// PASS: Animaciones de lista
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: Animaciones de modal
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>
  )
}

Patrones de Accesibilidad

Navegación por Teclado

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}
    >
      {/* Implementación del Dropdown */}
    </div>
  )
}

Gestión de Foco

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

  useEffect(() => {
    if (isOpen) {
      // Guardar elemento actualmente enfocado
      previousFocusRef.current = document.activeElement as HTMLElement

      // Enfocar modal
      modalRef.current?.focus()
    } else {
      // Restaurar foco al cerrar
      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
}

Recuerda: Los patrones modernos de frontend permiten interfaces de usuario mantenibles y de alto rendimiento. Elige los patrones que se ajusten a la complejidad de tu proyecto.

Repository: affaan-m/ECC
Path: docs/es/skills/frontend-patterns/SKILL.md
Commit: c70874f

Last updated: 1 day ago
First committed: 4 months ago

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