# Vue 3 Modernization
## Composition API
```vue
<script setup lang="ts">
import { ref, computed, onMounted } from 'vue'
// Reactive state
const count = ref(0)
const users = ref<User[]>([])
// Computed
const doubleCount = computed(() => count.value * 2)
// Methods
function increment() {
count.value++
}
// Lifecycle
onMounted(async () => {
users.value = await fetchUsers()
})
</script>
<template>
<div>
<p>Count: {{ count }}</p>
<p>Double: {{ doubleCount }}</p>
<button @click="increment">Add</button>
</div>
</template>
```
## State Management (Pinia)
```typescript
// stores/user.ts
import { defineStore } from 'pinia'
export const useUserStore = defineStore('user', {
state: () => ({
user: null as User | null,
isAuthenticated: false,
}),
getters: {
userName: (state) => state.user?.name ?? 'Guest',
},
actions: {
async login(credentials: Credentials) {
const user = await api.login(credentials)
this.user = user
this.isAuthenticated = true
},
logout() {
this.user = null
this.isAuthenticated = false
},
},
})
```
## Component Architecture
```
components/
├── Base/ # Button, Input, Card
├── Layout/ # Header, Sidebar, Footer
├── Features/ # Feature-specific components
└── Shared/ # Reusable across features
```
## Checklist
- [ ] Migrate to Composition API
- [ ] Set up Pinia for state
- [ ] Implement composables
- [ ] Add TypeScript
- [ ] Set up Vue Router
- [ ] Implement code splitting
Skills Directory