---
name: vue-frontend-expert
description: "Expert guide for Vue 3 (Composition API), Nuxt 3, and Pinia. Covers advanced reactive state management, `<script setup>` syntax, Vue Router, VueUse, and SPA/SSR architectural patterns in English and Indonesian."
author: "Roedy Rustam"
---

# Vue Frontend Expert (Vue 3 / Nuxt 3)

[English](#english) | [Bahasa Indonesia](#bahasa-indonesia)

---

<a name="english"></a>
## English

### Description
Production-grade guidance for building highly reactive and scalable frontend applications using **Vue 3 (Composition API)** and **Nuxt 3**. Covers the latest ecosystem tools including **Pinia** for state management, **VueUse** for composables, and **Tailwind CSS v4** integration.

### Trigger Conditions
Activate this skill when the user is:
- Scaffolding a new Vue 3 or Nuxt 3 project.
- Writing or refactoring Vue components using `<script setup>` and Composition API.
- Managing global state with Pinia.
- Handling client-side routing with Vue Router or Nuxt's file-based routing.
- Implementing SSR (Server-Side Rendering) or SSG (Static Site Generation) using Nuxt 3.

---

### Core Concepts

#### 1. Vue 3 Composition API & `<script setup>`
Use the `<script setup>` syntax by default. It provides better type inference, less boilerplate, and superior performance compared to the Options API.

```vue
<script setup lang="ts">
import { ref, computed, onMounted } from 'vue'

const count = ref(0)
const doubleCount = computed(() => count.value * 2)

function increment() {
  count.value++
}

onMounted(() => {
  console.log('Component is mounted!')
})
</script>

<template>
  <button @click="increment">Count is: {{ count }} (Double: {{ doubleCount }})</button>
</template>
```

#### 2. Global State Management (Pinia)
Pinia is the official state management library for Vue. Avoid Vuex in modern applications.

```typescript
// stores/counter.ts
import { defineStore } from 'pinia'
import { ref, computed } from 'vue'

export const useCounterStore = defineStore('counter', () => {
  const count = ref(0)
  const doubleCount = computed(() => count.value * 2)
  function increment() {
    count.value++
  }

  return { count, doubleCount, increment }
})
```

#### 3. Nuxt 3 Architecture
For SSR, SEO optimization, and file-based routing, use Nuxt 3.
- Data fetching: Use `useAsyncData` or `useFetch` to prevent hydration mismatches.
- Server API: Utilize the `server/api/` directory for Nitro API routes.

#### 4. The VueUse Collection
Always leverage [VueUse](https://vueuse.org/) for common composables (e.g., `useWindowSize`, `onClickOutside`, `useStorage`) instead of writing custom composables from scratch.

---

### Best Practices
1. **Ref vs Reactive:** Prefer `ref` for primitive values and `reactive` for deeply nested objects. When in doubt, default to `ref`.
2. **Define Macros:** Use `defineProps` and `defineEmits` in `<script setup>` for typed props and events.
3. **Avoid Watchers when possible:** Rely on `computed` properties instead of `watch` to derive state. Use `watch` only for side-effects (e.g., API calls, DOM manipulation).
4. **V-Model:** Use the updated `v-model` binding in Vue 3.4+ with `defineModel()` for cleaner two-way data binding between components.

---

### Integration with Other Skills (MANDATORY)

This skill works best when combined with:
- `design-system-architect` — To build headless UI components using Radix Vue or VueUse components.
- `tailwind-expert` — For styling Vue/Nuxt components with Tailwind CSS v4.
- `performance-web-vitals` — To optimize Nuxt 3 SSR metrics (LCP, INP).

### Referenced By Orchestrators (MANDATORY)

This skill should be referenced by the following orchestrators:
- `brainstorming` — Add to "Frontend Frameworks" row in the Matrix.
- `zero-to-prod-orchestrator` — Phase 5 (Frontend Implementation).

---

<a name="bahasa-indonesia"></a>
## Bahasa Indonesia

### Deskripsi
Panduan tingkat produksi untuk membangun aplikasi frontend reaktif dan terukur menggunakan **Vue 3 (Composition API)** dan **Nuxt 3**. Mencakup pengelolaan state dengan **Pinia**, utilitas **VueUse**, dan integrasi **Tailwind CSS v4**.

### Kondisi Pemicu
Aktifkan skill ini ketika pengguna sedang:
- Memulai proyek Vue 3 atau Nuxt 3 baru.
- Menulis ulang (refactoring) komponen ke `<script setup>` dan Composition API.
- Mengelola state global dengan Pinia (bukan Vuex).
- Menerapkan SSR (Server-Side Rendering) dengan Nuxt 3.

### Panduan Singkat

- **Composition API Default:** Selalu gunakan sintaks `<script setup lang="ts">`. Lebih ringkas, type-safe, dan efisien.
- **Pinia:** Gunakan Pinia dengan pola *Setup Store* (mirip Composition API) alih-alih pola Options (state, getters, actions).
- **Nuxt 3 Fetching:** Gunakan `useFetch` atau `useAsyncData` di dalam komponen Nuxt untuk pengambilan data saat SSR, bukan `onMounted` dengan `fetch` biasa.
- **Reaktivitas:** Gunakan `ref` untuk nilai primitif (string, number) dan `reactive` untuk objek bersarang yang kompleks. Utamakan `computed` daripada `watch` untuk state turunan.
- **VueUse:** Jangan menulis fungsi utilitas dari nol jika sudah ada di *library* VueUse (contoh: `useIntersectionObserver`, `useLocalStorage`).