---

name: frontend-development description: "Multi-framework frontend development. Frameworks: React 18+ (Suspense, hooks, TanStack), Vue 3 (Composition API, Pinia, Nuxt), Svelte 5 (Runes, SvelteKit), Angular (Signals, standalone). Common: TypeScript, state management, routing, data fetching, performance optimization, component patterns. Actions: create, build, implement, style, optimize, refactor components/pages/features. Keywords: React, Vue, Svelte, Angular, component, TypeScript, hooks, Composition API, runes, signals, useSuspenseQuery, Pinia, stores, state management, routing, lazy loading, Suspense, performance, bundle size, code splitting, reactivity, props, events. Use when: creating components in any framework, building pages, fetching data, implementing routing, state management, optimizing performance, organizing frontend code, choosing between frameworks."

Frontend Development Guidelines

Purpose

Comprehensive guide for modern frontend development across React, Vue 3, Svelte 5, and Angular. Covers framework-specific patterns, common architectural principles, and cross-framework best practices.

When to Use This Skill

• Creating components or pages in React, Vue, Svelte, or Angular
• Building new features with framework-specific patterns
• Implementing state management (Pinia, Zustand, stores, signals)
• Setting up routing (TanStack Router, Vue Router, SvelteKit, Angular Router)
• Data fetching patterns (TanStack Query, composables, SvelteKit load functions)
• Performance optimization across frameworks
• Component composition and reusability
• TypeScript integration and best practices
• Choosing the right framework for a project
• Migrating between frameworks

---

Framework Selection Guide

Choose your framework based on project requirements:

Framework	Best For	Learning Curve	Performance	Ecosystem
React	Large apps, strong typing, enterprise	Medium	Good	Largest
Vue 3	Progressive adoption, approachable	Low	Excellent	Growing
Svelte 5	Small/medium apps, native feel	Low	Best	Smaller
Angular	Enterprise, full-featured	Steep	Good	Complete

Quick Decision:

• Existing codebase? Use what's there or plan migration
• Team experience? Leverage existing knowledge
• Project size? Large → React/Angular, Medium → Vue/React, Small → Svelte/Vue
• Performance critical? Svelte > Vue > React ≈ Angular
• TypeScript required? All support it well (Angular best integrated)
• Ecosystem needs? React > Vue > Angular > Svelte

See framework-specific sections below for detailed patterns.

---

Quick Framework Comparison

Feature	React	Vue 3	Svelte 5	Angular
Reactivity	Hooks (useState)	ref/reactive	Runes ($state)	Signals
Components	JSX/TSX	SFC (.vue)	SFC (.svelte)	Decorators/Class
State Mgmt	Zustand/Context	Pinia	Stores	Services
Routing	React Router/TanStack	Vue Router	SvelteKit	Angular Router
Data Fetching	TanStack Query	Composables/VueQuery	Load functions	HttpClient/RxJS
Styling	CSS-in-JS/Modules	Scoped CSS	Scoped CSS	Component styles
Full-Stack	Next.js	Nuxt	SvelteKit	Universal/SSR
Bundle Size	~40KB	~32KB	~3KB	~60KB
Compiler	Runtime	Runtime	Compile-time	AOT Compiler

Jump to:

• React Development - Hooks, Suspense, TanStack ecosystem
• Vue 3 Development - Composition API, Pinia, Nuxt
• Svelte 5 Development - Runes, SvelteKit, minimal runtime
• Angular Development - Signals, standalone components, RxJS
• Framework-Agnostic Patterns - Universal concepts

---

React Development

New Component Checklist

Creating a component? Follow this checklist:

• Use React.FC<Props> pattern with TypeScript
• Lazy load if heavy component: React.lazy(() => import())
• Wrap in <SuspenseLoader> for loading states
• Use useSuspenseQuery for data fetching
• Import aliases: @/, ~types, ~components, ~features
• Styles: Inline if <100 lines, separate file if >100 lines
• Use useCallback for event handlers passed to children
• Default export at bottom
• No early returns with loading spinners
• Use useMuiSnackbar for user notifications

New Feature Checklist

Creating a feature? Set up this structure:

• Create features/{feature-name}/ directory
• Create subdirectories: api/, components/, hooks/, helpers/, types/
• Create API service file: api/{feature}Api.ts
• Set up TypeScript types in types/
• Create route in routes/{feature-name}/index.tsx
• Lazy load feature components
• Use Suspense boundaries
• Export public API from feature index.ts

---

Import Aliases Quick Reference

Alias	Resolves To	Example
@/	src/	import { apiClient } from '@/lib/apiClient'
~types	src/types	import type { User } from '~types/user'
~components	src/components	import { SuspenseLoader } from '~components/SuspenseLoader'
~features	src/features	import { authApi } from '~features/auth'

Defined in: vite.config.ts lines 180-185

---

Common Imports Cheatsheet

// React & Lazy Loading
import React, { useState, useCallback, useMemo } from 'react';
const Heavy = React.lazy(() => import('./Heavy'));

// MUI Components
import { Box, Paper, Typography, Button, Grid } from '@mui/material';
import type { SxProps, Theme } from '@mui/material';

// TanStack Query (Suspense)
import { useSuspenseQuery, useQueryClient } from '@tanstack/react-query';

// TanStack Router
import { createFileRoute } from '@tanstack/react-router';

// Project Components
import { SuspenseLoader } from '~components/SuspenseLoader';

// Hooks
import { useAuth } from '@/hooks/useAuth';
import { useMuiSnackbar } from '@/hooks/useMuiSnackbar';

// Types
import type { Post } from '~types/post';

---

Topic Guides

🎨 Component Patterns

Modern React components use:

• React.FC<Props> for type safety
• React.lazy() for code splitting
• SuspenseLoader for loading states
• Named const + default export pattern

Key Concepts:

• Lazy load heavy components (DataGrid, charts, editors)
• Always wrap lazy components in Suspense
• Use SuspenseLoader component (with fade animation)
• Component structure: Props → Hooks → Handlers → Render → Export

📖 Complete Guide: resources/component-patterns.md

---

📊 Data Fetching

PRIMARY PATTERN: useSuspenseQuery

• Use with Suspense boundaries
• Cache-first strategy (check grid cache before API)
• Replaces isLoading checks
• Type-safe with generics

API Service Layer:

• Create features/{feature}/api/{feature}Api.ts
• Use apiClient axios instance
• Centralized methods per feature
• Route format: /form/route (NOT /api/form/route)

📖 Complete Guide: resources/data-fetching.md

---

📁 File Organization

features/ vs components/:

• features/: Domain-specific (posts, comments, auth)
• components/: Truly reusable (SuspenseLoader, CustomAppBar)

Feature Subdirectories:

features/
  my-feature/
    api/          # API service layer
    components/   # Feature components
    hooks/        # Custom hooks
    helpers/      # Utility functions
    types/        # TypeScript types

📖 Complete Guide: resources/file-organization.md

---

🎨 Styling

Inline vs Separate:

• <100 lines: Inline const styles: Record<string, SxProps<Theme>>

• 100 lines: Separate .styles.ts file

Primary Method:

• Use sx prop for MUI components
• Type-safe with SxProps<Theme>
• Theme access: (theme) => theme.palette.primary.main

MUI v7 Grid:

<Grid size={{ xs: 12, md: 6 }}>  // ✅ v7 syntax
<Grid xs={12} md={6}>             // ❌ Old syntax

📖 Complete Guide: resources/styling-guide.md

---

🛣️ Routing

TanStack Router - Folder-Based:

• Directory: routes/my-route/index.tsx
• Lazy load components
• Use createFileRoute
• Breadcrumb data in loader

Example:

import { createFileRoute } from '@tanstack/react-router';
import { lazy } from 'react';

const MyPage = lazy(() => import('@/features/my-feature/components/MyPage'));

export const Route = createFileRoute('/my-route/')({
    component: MyPage,
    loader: () => ({ crumb: 'My Route' }),
});

📖 Complete Guide: resources/routing-guide.md

---

⏳ Loading & Error States

CRITICAL RULE: No Early Returns

// ❌ NEVER - Causes layout shift
if (isLoading) {
    return <LoadingSpinner />;
}

// ✅ ALWAYS - Consistent layout
<SuspenseLoader>
    <Content />
</SuspenseLoader>

Why: Prevents Cumulative Layout Shift (CLS), better UX

Error Handling:

• Use useMuiSnackbar for user feedback
• NEVER react-toastify
• TanStack Query onError callbacks

📖 Complete Guide: resources/loading-and-error-states.md

---

⚡ Performance

Optimization Patterns:

• useMemo: Expensive computations (filter, sort, map)
• useCallback: Event handlers passed to children
• React.memo: Expensive components
• Debounced search (300-500ms)
• Memory leak prevention (cleanup in useEffect)

📖 Complete Guide: resources/performance.md

---

📘 TypeScript

Standards:

• Strict mode, no any type
• Explicit return types on functions
• Type imports: import type { User } from '~types/user'
• Component prop interfaces with JSDoc

📖 Complete Guide: resources/typescript-standards.md

---

🔧 Common Patterns

Covered Topics:

• React Hook Form with Zod validation
• DataGrid wrapper contracts
• Dialog component standards
• useAuth hook for current user
• Mutation patterns with cache invalidation

📖 Complete Guide: resources/common-patterns.md

---

📚 Complete Examples

Full working examples:

• Modern component with all patterns
• Complete feature structure
• API service layer
• Route with lazy loading
• Suspense + useSuspenseQuery
• Form with validation

📖 Complete Guide: resources/complete-examples.md

---

React-Specific Navigation Guide

Need to...	Read this resource
Create a React component	component-patterns.md
Fetch data with TanStack Query	data-fetching.md
Organize files/folders	file-organization.md
Style with MUI v7	styling-guide.md
Set up TanStack Router	routing-guide.md
Handle loading/errors	loading-and-error-states.md
Optimize React performance	performance.md
TypeScript types	typescript-standards.md
Forms/Auth/DataGrid	common-patterns.md
See full React examples	complete-examples.md

Note: Resources above are React-specific. For Vue/Svelte/Angular, see framework sections in this document.

---

Core Principles (All Frameworks)

1. Lazy Load Heavy Components: Routes, data grids, charts, editors, modals
2. Consistent Loading States: Avoid layout shift with proper loading UI
3. Type Safety: Use TypeScript for all components and APIs
4. Component Composition: Small, focused components with clear responsibilities
5. Unidirectional Data Flow: Props down, events up
6. Performance First: Memoize expensive computations, virtual scrolling for lists
7. Organized Features: Group related code (components, state, types, utilities)
8. Framework Idioms: Use framework-specific patterns (hooks, composables, runes, services)

React-Specific Principles

1. useSuspenseQuery: Primary data fetching pattern for new code
2. No Early Returns: Prevents layout shift (use Suspense boundaries)
3. Import Aliases: Use @/, ~types, ~components, ~features
4. Styles Based on Size: <100 inline, >100 separate file

Vue-Specific Principles

1. Composition API: Prefer over Options API for reusability
2. Script Setup: Use for cleaner syntax and better performance
3. Composables: Extract reusable logic like React hooks
4. Pinia for State: Modern Vuex alternative with TypeScript support

Svelte-Specific Principles

1. Runes for Reactivity: Use $state, $derived, $effect (Svelte 5+)
2. SvelteKit for Apps: Leverage file-based routing and server functions
3. Minimal Stores: Runes reduce need for stores in components
4. Progressive Enhancement: Build for no-JS, enhance with JS

Angular-Specific Principles

1. Standalone Components: Default since v17 (avoid NgModules)
2. Signals for State: Prefer over RxJS for simple reactivity
3. OnPush Detection: Optimize change detection
4. Dependency Injection: Use inject() for modern DI

---

Quick Reference: File Structure

src/
  features/
    my-feature/
      api/
        myFeatureApi.ts       # API service
      components/
        MyFeature.tsx         # Main component
        SubComponent.tsx      # Related components
      hooks/
        useMyFeature.ts       # Custom hooks
        useSuspenseMyFeature.ts  # Suspense hooks
      helpers/
        myFeatureHelpers.ts   # Utilities
      types/
        index.ts              # TypeScript types
      index.ts                # Public exports

  components/
    SuspenseLoader/
      SuspenseLoader.tsx      # Reusable loader
    CustomAppBar/
      CustomAppBar.tsx        # Reusable app bar

  routes/
    my-route/
      index.tsx               # Route component
      create/
        index.tsx             # Nested route

---

Modern Component Template (Quick Copy)

import React, { useState, useCallback } from 'react';
import { Box, Paper } from '@mui/material';
import { useSuspenseQuery } from '@tanstack/react-query';
import { featureApi } from '../api/featureApi';
import type { FeatureData } from '~types/feature';

interface MyComponentProps {
    id: number;
    onAction?: () => void;
}

export const MyComponent: React.FC<MyComponentProps> = ({ id, onAction }) => {
    const [state, setState] = useState<string>('');

    const { data } = useSuspenseQuery({
        queryKey: ['feature', id],
        queryFn: () => featureApi.getFeature(id),
    });

    const handleAction = useCallback(() => {
        setState('updated');
        onAction?.();
    }, [onAction]);

    return (
        <Box sx={{ p: 2 }}>
            <Paper sx={{ p: 3 }}>
                {/* Content */}
            </Paper>
        </Box>
    );
};

export default MyComponent;

For complete examples, see resources/complete-examples.md

---

Vue 3 Development

Component Patterns

Composition API - Modern Vue 3 approach with <script setup>:

<script setup lang="ts">
import { ref, computed, onMounted } from 'vue'
import type { User } from '@/types/user'

interface Props {
  userId: number
}

const props = defineProps<Props>()
const emit = defineEmits<{
  update: [user: User]
}>()

const user = ref<User | null>(null)
const isLoading = ref(true)
const displayName = computed(() => user.value?.name ?? 'Unknown')

onMounted(async () => {
  user.value = await fetchUser(props.userId)
  isLoading.value = false
})

function handleUpdate() {
  if (user.value) emit('update', user.value)
}
</script>

<template>
  <div class="user-profile">
    <div v-if="isLoading">Loading...</div>
    <div v-else>
      <h2>{{ displayName }}</h2>
      <button @click="handleUpdate">Update</button>
    </div>
  </div>
</template>

<style scoped>
.user-profile {
  padding: 1rem;
}
</style>

Key Patterns:

• <script setup> - Concise composition API syntax
• defineProps<T>() - Type-safe props with generics
• defineEmits<T>() - Type-safe events
• ref(), reactive() - Reactivity primitives
• computed() - Derived state
• watch(), watchEffect() - Side effects
• onMounted, onUnmounted - Lifecycle hooks

State Management (Pinia)

// stores/userStore.ts
import { defineStore } from 'pinia'
import { ref, computed } from 'vue'

export const useUserStore = defineStore('user', () => {
  // State
  const users = ref<User[]>([])
  const currentUser = ref<User | null>(null)

  // Getters
  const userCount = computed(() => users.value.length)
  const isAuthenticated = computed(() => currentUser.value !== null)

  // Actions
  async function fetchUsers() {
    users.value = await api.getUsers()
  }

  function setCurrentUser(user: User) {
    currentUser.value = user
  }

  return { users, currentUser, userCount, isAuthenticated, fetchUsers, setCurrentUser }
})

// Component usage
<script setup lang="ts">
import { useUserStore } from '@/stores/userStore'
const userStore = useUserStore()
</script>

Routing (Vue Router)

// router/index.ts
import { createRouter, createWebHistory } from 'vue-router'

const router = createRouter({
  history: createWebHistory(),
  routes: [
    {
      path: '/',
      component: () => import('@/views/HomeView.vue')
    },
    {
      path: '/users/:id',
      component: () => import('@/views/UserView.vue'),
      props: true
    }
  ]
})

// Component with route params
<script setup lang="ts">
import { useRoute, useRouter } from 'vue-router'

const route = useRoute()
const router = useRouter()
const userId = route.params.id

function goBack() {
  router.push('/')
}
</script>

Data Fetching Patterns

Composables - Reusable logic:

// composables/useUser.ts
import { ref, type Ref } from 'vue'

export function useUser(id: Ref<number>) {
  const user = ref<User | null>(null)
  const loading = ref(false)
  const error = ref<Error | null>(null)

  async function fetchUser() {
    loading.value = true
    try {
      user.value = await api.getUser(id.value)
    } catch (e) {
      error.value = e as Error
    } finally {
      loading.value = false
    }
  }

  watchEffect(() => {
    fetchUser()
  })

  return { user, loading, error, refetch: fetchUser }
}

// Usage in component
<script setup lang="ts">
const props = defineProps<{ userId: number }>()
const { user, loading, error } = useUser(toRef(props, 'userId'))
</script>

Nuxt.js Server-Side:

<script setup lang="ts">
// Nuxt auto-imports composables
const { data: user, pending, error } = await useFetch(`/api/users/${route.params.id}`)
</script>

Vue 3 Best Practices

• Composition API over Options API - Better TypeScript support, reusability
• Script setup - Reduces boilerplate, automatic registration
• Pinia over Vuex - Simpler API, better TypeScript, composition API compatible
• Composables - Extract reusable logic (like React hooks)
• v-memo - Optimize expensive renders (similar to React.memo)
• defineOptions - Set component options in script setup
• Shallow reactive - Use shallowRef() for large objects

---

Svelte 5 Development

Runes-Based Reactivity

Svelte 5 Runes - New reactivity system:

<script lang="ts">
import type { User } from '$lib/types/user'

interface Props {
  userId: number
  onUpdate?: (user: User) => void
}

let { userId, onUpdate }: Props = $props()

// Reactive state with $state
let user = $state<User | null>(null)
let isLoading = $state(true)

// Derived state with $derived
let displayName = $derived(user?.name ?? 'Unknown')
let userAge = $derived.by(() => {
  if (!user?.birthDate) return null
  return calculateAge(user.birthDate)
})

// Effects with $effect
$effect(() => {
  // Runs when userId changes
  loadUser(userId)
})

async function loadUser(id: number) {
  isLoading = true
  user = await fetchUser(id)
  isLoading = false
}

function handleUpdate() {
  if (user) onUpdate?.(user)
}
</script>

{#if isLoading}
  <div>Loading...</div>
{:else if user}
  <div class="user-profile">
    <h2>{displayName}</h2>
    {#if userAge}
      <p>Age: {userAge}</p>
    {/if}
    <button onclick={handleUpdate}>Update</button>
  </div>
{/if}

<style>
.user-profile {
  padding: 1rem;
}
</style>

Svelte 5 Runes:

• $state() - Reactive state (replaces let for reactivity)
• $derived - Computed values (replaces $:)
• $derived.by() - Complex derived state
• $effect() - Side effects (replaces $: statements)
• $props() - Component props with destructuring
• $bindable() - Two-way binding for props
• $inspect() - Debugging reactive values

State Management (Svelte Stores)

// stores/user.ts
import { writable, derived, readonly } from 'svelte/store'

function createUserStore() {
  const { subscribe, set, update } = writable<User[]>([])

  return {
    subscribe,
    setUsers: (users: User[]) => set(users),
    addUser: (user: User) => update(users => [...users, user]),
    removeUser: (id: number) => update(users => users.filter(u => u.id !== id)),
    reset: () => set([])
  }
}

export const users = createUserStore()
export const userCount = derived(users, $users => $users.length)

// Component usage (Svelte 4 style)
<script>
import { users } from '$lib/stores/user'
</script>

<p>Total users: {$users.length}</p>

// Or with runes (Svelte 5)
<script>
import { users } from '$lib/stores/user'
let currentUsers = $state($users)
</script>

SvelteKit Routing & Data Loading

// src/routes/users/[id]/+page.ts
import type { PageLoad } from './$types'

export const load: PageLoad = async ({ params, fetch }) => {
  const user = await fetch(`/api/users/${params.id}`).then(r => r.json())

  return {
    user
  }
}

// src/routes/users/[id]/+page.svelte
<script lang="ts">
import type { PageData } from './$types'

let { data }: { data: PageData } = $props()
let { user } = $derived(data)
</script>

<h1>{user.name}</h1>

SvelteKit Patterns:

• +page.svelte - Page component
• +page.ts - Page data loading (runs on server and client)
• +page.server.ts - Server-only load functions
• +layout.svelte - Shared layouts
• +server.ts - API endpoints
• Form actions - Progressive enhancement

Svelte 5 Best Practices

• Use Runes - Modern reactivity (Svelte 5+)
• Explicit reactivity - Use $state() instead of implicit let
• $derived over $: - Clearer intent, better optimization
• Component composition - Use slots and snippets
• SvelteKit for apps - Full-stack framework with routing, SSR
• Minimize stores - Runes reduce need for stores in components
• Progressive enhancement - Use form actions for better UX

---

Angular Development

Standalone Components (Modern)

// user-profile.component.ts
import { Component, Input, Output, EventEmitter, signal, computed } from '@angular/core'
import { CommonModule } from '@angular/common'
import type { User } from '@/types/user'

@Component({
  selector: 'app-user-profile',
  standalone: true,
  imports: [CommonModule],
  template: `
    <div class="user-profile" *ngIf="!isLoading(); else loading">
      <h2>{{ displayName() }}</h2>
      <p>Age: {{ userAge() }}</p>
      <button (click)="handleUpdate()">Update</button>
    </div>
    <ng-template #loading>
      <div>Loading...</div>
    </ng-template>
  `,
  styles: [`
    .user-profile {
      padding: 1rem;
    }
  `]
})
export class UserProfileComponent {
  @Input({ required: true }) userId!: number
  @Output() userUpdate = new EventEmitter<User>()

  // Signals - reactive primitives
  user = signal<User | null>(null)
  isLoading = signal(true)

  // Computed signals
  displayName = computed(() => this.user()?.name ?? 'Unknown')
  userAge = computed(() => {
    const birthDate = this.user()?.birthDate
    return birthDate ? this.calculateAge(birthDate) : null
  })

  async ngOnInit() {
    this.user.set(await this.fetchUser(this.userId))
    this.isLoading.set(false)
  }

  handleUpdate() {
    const currentUser = this.user()
    if (currentUser) this.userUpdate.emit(currentUser)
  }
}

Angular Signals - New reactivity system (v16+):

• signal() - Writable reactive value
• computed() - Derived state
• effect() - Side effects
• .set(), .update() - Modify signal values
• () - Read signal value (call as function)

State Management (Services + Signals)

// services/user.service.ts
import { Injectable, signal, computed } from '@angular/core'
import { HttpClient } from '@angular/common/http'

@Injectable({ providedIn: 'root' })
export class UserService {
  private users = signal<User[]>([])
  private currentUser = signal<User | null>(null)

  // Public computed signals
  readonly userCount = computed(() => this.users().length)
  readonly isAuthenticated = computed(() => this.currentUser() !== null)

  constructor(private http: HttpClient) {}

  async fetchUsers() {
    const users = await this.http.get<User[]>('/api/users').toPromise()
    this.users.set(users)
  }

  setCurrentUser(user: User) {
    this.currentUser.set(user)
  }
}

// Component usage
export class MyComponent {
  constructor(public userService: UserService) {}

  // Access in template
  // {{ userService.userCount() }}
}

Routing (Angular Router)

// app.routes.ts
import { Routes } from '@angular/router'

export const routes: Routes = [
  {
    path: '',
    loadComponent: () => import('./home/home.component').then(m => m.HomeComponent)
  },
  {
    path: 'users/:id',
    loadComponent: () => import('./users/user-detail.component').then(m => m.UserDetailComponent)
  }
]

// Component with route params
import { Component } from '@angular/core'
import { ActivatedRoute, Router } from '@angular/router'

export class UserDetailComponent {
  userId = signal<string>('')

  constructor(
    private route: ActivatedRoute,
    private router: Router
  ) {
    this.userId.set(this.route.snapshot.paramMap.get('id') ?? '')
  }

  goBack() {
    this.router.navigate(['/'])
  }
}

Data Fetching (RxJS + Signals)

import { Component, signal } from '@angular/core'
import { HttpClient } from '@angular/common/http'
import { toSignal } from '@angular/core/rxjs-interop'

export class UserListComponent {
  private http = inject(HttpClient)

  // Convert Observable to Signal
  users = toSignal(this.http.get<User[]>('/api/users'), { initialValue: [] })

  // Or manual signal management
  manualUsers = signal<User[]>([])

  async loadUsers() {
    const users = await this.http.get<User[]>('/api/users').toPromise()
    this.manualUsers.set(users)
  }
}

Angular Best Practices

• Standalone components - Default since v17 (no NgModules)
• Signals over RxJS - Simpler reactivity for state
• toSignal - Convert Observables to Signals when needed
• inject() - Modern dependency injection (no constructor)
• Lazy loading - Use loadComponent for routes
• OnPush change detection - Optimize rendering
• Typed forms - Use FormGroup<T> for type safety

---

Framework-Agnostic Patterns

State Management Comparison

Pattern	React	Vue 3	Svelte 5	Angular
Local State	useState	ref()	$state()	signal()
Derived State	useMemo	computed()	$derived	computed()
Side Effects	useEffect	watch/watchEffect	$effect()	effect()
Global State	Zustand/Context	Pinia	Stores	Services
Async State	TanStack Query	VueQuery/Composables	Stores	RxJS/Signals

Component Composition Patterns

Props/Events Pattern (All frameworks):

• Parent passes data down via props
• Child emits events upward
• Unidirectional data flow

Slots/Children Pattern:

// React
<Layout>
  <Header />
  <Content />
</Layout>

// Vue
<Layout>
  <template #header><Header /></template>
  <template #content><Content /></template>
</Layout>

// Svelte
<Layout>
  <Header slot="header" />
  <Content slot="content" />
</Layout>

// Angular
<app-layout>
  <app-header header></app-header>
  <app-content content></app-content>
</app-layout>

Routing Patterns

File-Based Routing:

• Next.js (React), Nuxt (Vue), SvelteKit (Svelte)
• Folder structure defines routes
• [id] for dynamic segments

Programmatic Routing:

• React Router, Vue Router, Angular Router
• Define routes in config
• More flexible but more verbose

Performance Optimization

Universal Techniques:

1. Code splitting - Lazy load routes and heavy components
2. Memoization - Cache expensive computations
3. Virtual scrolling - Render only visible items
4. Debouncing - Throttle expensive operations (search, resize)
5. Image optimization - Lazy load, responsive images, modern formats
6. Bundle analysis - Identify and remove large dependencies

Framework-Specific:

• React: React.memo, useMemo, useCallback, Suspense
• Vue: v-memo, shallowRef, markRaw, KeepAlive
• Svelte: Automatic optimization, $derived, minimal runtime
• Angular: OnPush, signals, trackBy, pure pipes

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Related Skills

UI/Design:

• ui-design-system: Component design systems, accessibility, design tokens
• ui-ux-pro-max: UI/UX design principles, visual hierarchy, color theory
• ui-styling: Tailwind CSS, styling patterns for all frameworks

Backend Integration:

• backend-development: API patterns that frontend consumes
• better-auth: Authentication implementation (works with all frameworks)

Full-Stack Frameworks:

• web-frameworks: Next.js (React), Nuxt (Vue), SvelteKit (Svelte) deep dive

Development:

• debugging: Framework-agnostic debugging strategies
• refactoring-expert: Code quality and refactoring patterns
• chrome-devtools: Browser debugging, performance profiling

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Skill Status: Multi-framework coverage with progressive disclosure