frontend-patternslisted

# Frontend Development Patterns Modern frontend patterns for React, Next.js, and performant user interfaces. ## When to Activate - 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 // ✅ 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: Reac