Vue

mizu new ./my-vue-app --template frontend/vue
cd my-vue-app
make dev

┌─────────────────────────────────────────────────────────────┐
│                         Browser                              │
│  ┌───────────────────────────────────────────────────────┐  │
│  │  Vue App (HMR enabled)                                 │  │
│  │  ┌─────────┐  ┌─────────┐  ┌──────────┐               │  │
│  │  │ Router  │→ │ Pages   │→ │ API Call │               │  │
│  │  └─────────┘  └─────────┘  └──────────┘               │  │
│  └───────────────────────────────────────────────────────┘  │
│         ↑ HMR WebSocket           ↓ /api/users              │
└─────────┼──────────────────────────┼────────────────────────┘
          │                          │
┌─────────┼──────────────────────────┼────────────────────────┐
│  Mizu Server (:3000)               │                         │
│         │                          ↓                         │
│    ┌────┴─────────┐        ┌────────────┐                   │
│    │   Proxy to   │        │ API Routes │                   │
│    │ Vite (:5173) │        │ (Go)       │                   │
│    └──────────────┘        └────────────┘                   │
│         ↑                                                    │
└─────────┼────────────────────────────────────────────────────┘
          │
┌─────────┼────────────────────────────────────────────────────┐
│  Vite Dev Server (:5173)                                     │
│    ┌──────────────┐  ┌─────────────┐                        │
│    │ Vue Compiler │  │ HMR Engine  │                        │
│    └──────────────┘  └─────────────┘                        │
└──────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│                         Browser                              │
│  ┌───────────────────────────────────────────────────────┐  │
│  │  Vue App (compiled, minified)                          │  │
│  │  ┌─────────┐  ┌─────────┐  ┌──────────┐               │  │
│  │  │ Router  │→ │ Pages   │→ │ API Call │               │  │
│  │  └─────────┘  └─────────┘  └──────────┘               │  │
│  └───────────────────────────────────────────────────────┘  │
│         ↑ index.html + assets     ↓ /api/users              │
└─────────┼──────────────────────────┼────────────────────────┘
          │                          │
┌─────────┼──────────────────────────┼────────────────────────┐
│  Mizu Server (single binary)       │                         │
│         │                          ↓                         │
│    ┌────┴─────────┐        ┌────────────┐                   │
│    │ Embedded FS  │        │ API Routes │                   │
│    │ (dist/...)   │        │ (Go)       │                   │
│    └──────────────┘        └────────────┘                   │
│  ←────────────────────────────────────────────────────────  │
│  Static files served from Go binary (//go:embed all:dist)   │
└──────────────────────────────────────────────────────────────┘

my-vue-app/
├── cmd/
│   └── server/
│       └── main.go              # Entry point
├── app/
│   └── server/
│       ├── app.go               # Mizu app setup
│       ├── config.go            # Configuration
│       └── routes.go            # API routes
├── frontend/                      # Vue application
│   ├── src/
│   │   ├── main.ts              # Vue entry point
│   │   ├── App.vue              # Root component
│   │   ├── router/
│   │   │   └── index.ts         # Vue Router
│   │   ├── components/
│   │   │   └── Layout.vue       # Layout component
│   │   ├── pages/
│   │   │   ├── Home.vue         # Home page
│   │   │   └── About.vue        # About page
│   │   ├── stores/              # Pinia stores
│   │   ├── composables/         # Custom composables
│   │   └── styles/
│   │       └── index.css        # Global styles
│   ├── public/
│   │   └── vite.svg             # Public assets
│   ├── index.html               # HTML template
│   ├── package.json             # npm dependencies
│   ├── vite.config.ts           # Vite configuration
│   ├── tsconfig.json            # TypeScript config
│   └── env.d.ts                 # TypeScript declarations
├── dist/                        # Built files (after build)
├── go.mod
└── Makefile

package server

import (
    "embed"
    "io/fs"

    "github.com/go-mizu/mizu"
    "github.com/go-mizu/mizu/frontend"
)

//go:embed all:../../dist
var distFS embed.FS

func New(cfg *Config) *mizu.App {
    app := mizu.New()

    // API routes
    setupRoutes(app)

    // Frontend middleware
    dist, _ := fs.Sub(distFS, "dist")
    app.Use(frontend.WithOptions(frontend.Options{
        Mode:        frontend.ModeAuto,
        FS:          dist,
        DevServer:   "http://localhost:" + cfg.DevPort,
        IgnorePaths: []string{"/api"},
    }))

    return app
}

// app/server/routes.go
package server

import "github.com/go-mizu/mizu"

type User struct {
    ID    int    `json:"id"`
    Name  string `json:"name"`
    Email string `json:"email"`
}

func setupRoutes(app *mizu.App) {
    // GET /api/users
    app.GET("/api/users", func(c *mizu.Ctx) error {
        users := []User{
            {ID: 1, Name: "Alice", Email: "[email protected]"},
            {ID: 2, Name: "Bob", Email: "[email protected]"},
        }
        return c.JSON(users)
    })

    // POST /api/users
    app.POST("/api/users", func(c *mizu.Ctx) error {
        var user User
        if err := c.BodyParser(&user); err != nil {
            return err
        }
        user.ID = 3 // In real app, generate from DB
        return c.Status(201).JSON(user)
    })

    // GET /api/users/:id
    app.GET("/api/users/:id", func(c *mizu.Ctx) error {
        id := c.Param("id")
        user := User{ID: 1, Name: "Alice", Email: "[email protected]"}
        return c.JSON(user)
    })

    // DELETE /api/users/:id
    app.DELETE("/api/users/:id", func(c *mizu.Ctx) error {
        return c.Status(204).Send(nil)
    })
}

import { createApp } from 'vue'
import App from './App.vue'
import router from './router'
import './styles/index.css'

createApp(App)
  .use(router)
  .mount('#app')

<template>
  <router-view />
</template>

<script setup lang="ts">
// No script needed for basic setup
</script>

import { createRouter, createWebHistory } from 'vue-router'
import Layout from '@/components/Layout.vue'
import Home from '@/pages/Home.vue'
import About from '@/pages/About.vue'

const router = createRouter({
  history: createWebHistory(),
  routes: [
    {
      path: '/',
      component: Layout,
      children: [
        { path: '', component: Home },
        { path: 'about', component: About },
      ],
    },
  ],
})

export default router

<template>
  <div class="app">
    <nav>
      <router-link to="/">Home</router-link>
      <router-link to="/about">About</router-link>
    </nav>

    <main>
      <router-view />
    </main>

    <footer>
      <p>Built with Mizu and Vue</p>
    </footer>
  </div>
</template>

<style scoped>
nav {
  display: flex;
  gap: 1rem;
  padding: 1rem;
  background: #f5f5f5;
}

nav a {
  color: #42b983;
  text-decoration: none;
}

nav a.router-link-active {
  font-weight: bold;
}
</style>

<template>
  <div>
    <h1>Users</h1>

    <div v-if="loading">Loading...</div>
    <div v-else-if="error">Error: {{ error }}</div>
    <ul v-else>
      <li v-for="user in users" :key="user.id">
        {{ user.name }} ({{ user.email }})
      </li>
    </ul>
  </div>
</template>

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

interface User {
  id: number
  name: string
  email: string
}

const users = ref<User[]>([])
const loading = ref(true)
const error = ref<string | null>(null)

onMounted(async () => {
  try {
    const response = await fetch('/api/users')
    if (!response.ok) throw new Error('Failed to fetch users')
    users.value = await response.json()
  } catch (err) {
    error.value = err instanceof Error ? err.message : 'Unknown error'
  } finally {
    loading.value = false
  }
})
</script>

<template>
  <div>
    <p>Count: {{ count }}</p>
    <button @click="increment">Increment</button>
  </div>
</template>

<script lang="ts">
import { defineComponent } from 'vue'

export default defineComponent({
  data() {
    return {
      count: 0
    }
  },
  computed: {
    doubled() {
      return this.count * 2
    }
  },
  methods: {
    increment() {
      this.count++
    }
  },
  mounted() {
    console.log('Component mounted')
  }
})
</script>

<template>
  <div>
    <p>Count: {{ count }}</p>
    <button @click="increment">Increment</button>
  </div>
</template>

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

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

function increment() {
  count.value++
}

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

<script setup lang="ts">
import { ref } from 'vue'

const count = ref(0)
const name = ref('Alice')
const isActive = ref(true)

// Access with .value in script
console.log(count.value) // 0
count.value++

// Update
function increment() {
  count.value++
}
</script>

<template>
  <!-- No .value in template -->
  <p>Count: {{ count }}</p>
  <p>Name: {{ name }}</p>
  <button @click="increment">+</button>
</template>

<script setup lang="ts">
import { reactive } from 'vue'

interface User {
  name: string
  age: number
  hobbies: string[]
}

const user = reactive<User>({
  name: 'Alice',
  age: 30,
  hobbies: ['reading', 'coding']
})

// Access directly (no .value)
console.log(user.name) // 'Alice'
user.age++
user.hobbies.push('gaming')
</script>

<template>
  <div>
    <p>{{ user.name }}, {{ user.age }}</p>
    <ul>
      <li v-for="hobby in user.hobbies" :key="hobby">{{ hobby }}</li>
    </ul>
  </div>
</template>

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

const firstName = ref('John')
const lastName = ref('Doe')

// Cached, only recomputes when firstName or lastName change
const fullName = computed(() => {
  console.log('Computing full name')
  return `${firstName.value} ${lastName.value}`
})

// Writable computed
const fullNameWritable = computed({
  get() {
    return `${firstName.value} ${lastName.value}`
  },
  set(value: string) {
    const parts = value.split(' ')
    firstName.value = parts[0]
    lastName.value = parts[1] || ''
  }
})
</script>

<template>
  <div>
    <p>{{ fullName }}</p>
    <input v-model="firstName" />
    <input v-model="lastName" />
  </div>
</template>

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

const count = ref(0)
const user = reactive({ name: 'Alice', age: 30 })

// Watch a single ref
watch(count, (newVal, oldVal) => {
  console.log(`Count changed from ${oldVal} to ${newVal}`)
})

// Watch a getter function
watch(
  () => user.name,
  (newName) => {
    console.log(`Name changed to ${newName}`)
  }
)

// Watch multiple sources
watch([count, () => user.name], ([newCount, newName]) => {
  console.log(`Count: ${newCount}, Name: ${newName}`)
})

// Deep watch for objects
watch(
  user,
  (newUser) => {
    console.log('User changed:', newUser)
  },
  { deep: true }
)

// Immediate execution
watch(count, (val) => {
  console.log('Count:', val)
}, { immediate: true })
</script>

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

const count = ref(0)
const doubled = ref(0)

// Automatically tracks count, runs immediately
watchEffect(() => {
  doubled.value = count.value * 2
  console.log('Doubled:', doubled.value)
})

// With cleanup
watchEffect((onCleanup) => {
  const timer = setTimeout(() => {
    console.log('Count:', count.value)
  }, 1000)

  onCleanup(() => {
    clearTimeout(timer)
  })
})
</script>

<script setup lang="ts">
import {
  onBeforeMount,
  onMounted,
  onBeforeUpdate,
  onUpdated,
  onBeforeUnmount,
  onUnmounted,
  ref
} from 'vue'

const count = ref(0)

onBeforeMount(() => {
  console.log('Before mount: DOM not created yet')
})

onMounted(() => {
  console.log('Mounted: Component is in DOM')
  // Good for: API calls, DOM manipulation, timers
  fetchData()
})

onBeforeUpdate(() => {
  console.log('Before update: Before DOM re-render')
})

onUpdated(() => {
  console.log('Updated: After DOM re-render')
  // Be careful: can cause infinite loops
})

onBeforeUnmount(() => {
  console.log('Before unmount: Cleanup starting')
})

onUnmounted(() => {
  console.log('Unmounted: Component removed from DOM')
  // Good for: Cleanup timers, subscriptions, listeners
})

async function fetchData() {
  const res = await fetch('/api/data')
  const data = await res.json()
  console.log(data)
}
</script>

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

const router = createRouter({
  history: createWebHistory(),
  routes: [
    {
      path: '/users/:id',
      component: () => import('@/pages/UserDetail.vue'),
      props: true  // Pass :id as prop to component
    },
    {
      path: '/posts/:id(\\d+)',  // Only match numeric IDs
      component: () => import('@/pages/PostDetail.vue')
    },
    {
      // Catch-all route for 404
      path: '/:pathMatch(.*)*',
      component: () => import('@/pages/NotFound.vue')
    }
  ]
})

export default router

<!-- pages/UserDetail.vue -->
<template>
  <div>
    <h1>User {{ id }}</h1>
    <div v-if="loading">Loading...</div>
    <div v-else-if="user">
      <p>Name: {{ user.name }}</p>
      <p>Email: {{ user.email }}</p>
    </div>
  </div>
</template>

<script setup lang="ts">
import { ref, onMounted, watch } from 'vue'
import { useRoute } from 'vue-router'

// Option 1: Use props (requires props: true in route)
const props = defineProps<{ id: string }>()

// Option 2: Use useRoute()
const route = useRoute()

interface User {
  name: string
  email: string
}

const user = ref<User | null>(null)
const loading = ref(true)

async function fetchUser(id: string) {
  loading.value = true
  const res = await fetch(`/api/users/${id}`)
  user.value = await res.json()
  loading.value = false
}

onMounted(() => {
  fetchUser(props.id)
})

// Re-fetch when ID changes (same component, different route)
watch(() => props.id, (newId) => {
  fetchUser(newId)
})
</script>

// router/index.ts
const router = createRouter({
  history: createWebHistory(),
  routes: [
    {
      path: '/dashboard',
      component: () => import('@/layouts/DashboardLayout.vue'),
      children: [
        {
          path: '',  // /dashboard
          component: () => import('@/pages/DashboardHome.vue')
        },
        {
          path: 'settings',  // /dashboard/settings
          component: () => import('@/pages/Settings.vue')
        },
        {
          path: 'users',  // /dashboard/users
          component: () => import('@/pages/Users.vue')
        }
      ]
    }
  ]
})

<!-- layouts/DashboardLayout.vue -->
<template>
  <div class="dashboard">
    <aside>
      <nav>
        <router-link to="/dashboard">Home</router-link>
        <router-link to="/dashboard/settings">Settings</router-link>
        <router-link to="/dashboard/users">Users</router-link>
      </nav>
    </aside>

    <main>
      <!-- Child routes render here -->
      <router-view />
    </main>
  </div>
</template>

<script setup lang="ts">
import { useRouter, useRoute } from 'vue-router'

const router = useRouter()
const route = useRoute()

function goToUser(id: number) {
  // Navigate to route
  router.push(`/users/${id}`)

  // Or with object
  router.push({ path: `/users/${id}` })

  // Or with named route
  router.push({ name: 'user', params: { id } })
}

function goBack() {
  router.back()
}

function replaceRoute() {
  // Replace current history entry (no back button)
  router.replace('/home')
}

// Access current route
console.log(route.params.id)
console.log(route.query.search)
console.log(route.path)
</script>

<template>
  <button @click="goToUser(123)">View User 123</button>
  <button @click="goBack">Go Back</button>
</template>

// router/index.ts
const router = createRouter({
  history: createWebHistory(),
  routes: [
    {
      path: '/admin',
      component: () => import('@/pages/Admin.vue'),
      meta: { requiresAuth: true }
    }
  ]
})

// Global before guard
router.beforeEach((to, from, next) => {
  const isAuthenticated = localStorage.getItem('token')

  if (to.meta.requiresAuth && !isAuthenticated) {
    // Redirect to login
    next('/login')
  } else {
    next()
  }
})

// Global after guard
router.afterEach((to, from) => {
  // Update document title
  document.title = to.meta.title as string || 'My App'
})

export default router

// Per-route guard
const routes = [
  {
    path: '/users/:id',
    component: UserDetail,
    beforeEnter: (to, from) => {
      const id = parseInt(to.params.id as string)
      if (isNaN(id)) {
        return { path: '/404' }
      }
    }
  }
]

<!-- In-component guard -->
<script setup lang="ts">
import { onBeforeRouteLeave, onBeforeRouteUpdate } from 'vue-router'

const hasUnsavedChanges = ref(false)

onBeforeRouteLeave((to, from) => {
  if (hasUnsavedChanges.value) {
    const answer = window.confirm('You have unsaved changes. Leave anyway?')
    if (!answer) return false
  }
})

onBeforeRouteUpdate((to, from) => {
  // Called when route changes but component is reused
  console.log('Route updated:', to.params)
})
</script>

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import path from 'path'

export default defineConfig({
  plugins: [vue()],

  resolve: {
    alias: {
      '@': path.resolve(__dirname, './src'),
      '@components': path.resolve(__dirname, './src/components'),
      '@pages': path.resolve(__dirname, './src/pages'),
      '@stores': path.resolve(__dirname, './src/stores'),
      '@composables': path.resolve(__dirname, './src/composables'),
    },
  },

  server: {
    port: 5173,
    strictPort: true,
    hmr: {
      clientPort: 3000,  // Mizu's port for HMR WebSocket
    },
  },

  build: {
    outDir: '../dist',
    emptyOutDir: true,
    sourcemap: false,
    rollupOptions: {
      output: {
        manualChunks: {
          'vue-vendor': ['vue', 'vue-router'],
          'pinia': ['pinia'],
        },
      },
    },
  },
})

{
  "compilerOptions": {
    "paths": {
      "@/*": ["./src/*"],
      "@components/*": ["./src/components/*"],
      "@pages/*": ["./src/pages/*"],
      "@stores/*": ["./src/stores/*"],
      "@composables/*": ["./src/composables/*"]
    }
  }
}

// src/composables/useApi.ts
import { ref, unref, type Ref } from 'vue'

interface UseApiOptions {
  immediate?: boolean
}

export function useApi<T>(url: string | Ref<string>, options: UseApiOptions = {}) {
  const data = ref<T | null>(null)
  const loading = ref(false)
  const error = ref<Error | null>(null)

  const execute = async () => {
    loading.value = true
    error.value = null

    try {
      const response = await fetch(unref(url))
      if (!response.ok) throw new Error(`HTTP error! status: ${response.status}`)
      data.value = await response.json()
    } catch (err) {
      error.value = err instanceof Error ? err : new Error('Unknown error')
    } finally {
      loading.value = false
    }
  }

  if (options.immediate) {
    execute()
  }

  return { data, loading, error, execute, refetch: execute }
}

<!-- Usage -->
<script setup lang="ts">
import { useApi } from '@/composables/useApi'

interface User {
  id: number
  name: string
}

const { data: users, loading, error, refetch } = useApi<User[]>('/api/users', {
  immediate: true
})
</script>

<template>
  <div>
    <button @click="refetch">Refresh</button>
    <div v-if="loading">Loading...</div>
    <div v-else-if="error">Error: {{ error.message }}</div>
    <ul v-else>
      <li v-for="user in users" :key="user.id">{{ user.name }}</li>
    </ul>
  </div>
</template>

// src/composables/useDebounce.ts
import { ref, watch, unref, type Ref } from 'vue'

export function useDebounce<T>(value: Ref<T>, delay = 300) {
  const debouncedValue = ref(value.value) as Ref<T>

  let timeout: ReturnType<typeof setTimeout> | null = null

  watch(value, (newVal) => {
    if (timeout) clearTimeout(timeout)

    timeout = setTimeout(() => {
      debouncedValue.value = newVal
    }, delay)
  })

  return debouncedValue
}

<!-- Usage: Search with debouncing -->
<script setup lang="ts">
import { ref, watch } from 'vue'
import { useDebounce } from '@/composables/useDebounce'

const searchQuery = ref('')
const debouncedQuery = useDebounce(searchQuery, 500)
const results = ref([])

watch(debouncedQuery, async (query) => {
  if (!query) {
    results.value = []
    return
  }

  const res = await fetch(`/api/search?q=${query}`)
  results.value = await res.json()
})
</script>

<template>
  <input v-model="searchQuery" placeholder="Search..." />
  <!-- Results update 500ms after user stops typing -->
  <ul>
    <li v-for="result in results" :key="result.id">{{ result.name }}</li>
  </ul>
</template>

// src/composables/useLocalStorage.ts
import { ref, watch, type Ref } from 'vue'

export function useLocalStorage<T>(key: string, defaultValue: T): Ref<T> {
  const storedValue = localStorage.getItem(key)
  const data = ref<T>(
    storedValue ? JSON.parse(storedValue) : defaultValue
  ) as Ref<T>

  watch(
    data,
    (newValue) => {
      localStorage.setItem(key, JSON.stringify(newValue))
    },
    { deep: true }
  )

  return data
}

<!-- Usage -->
<script setup lang="ts">
import { useLocalStorage } from '@/composables/useLocalStorage'

// Automatically synced with localStorage
const preferences = useLocalStorage('user-preferences', {
  theme: 'light',
  fontSize: 14
})
</script>

<template>
  <div>
    <select v-model="preferences.theme">
      <option value="light">Light</option>
      <option value="dark">Dark</option>
    </select>
    <input v-model.number="preferences.fontSize" type="number" />
  </div>
</template>

cd frontend
npm install pinia

// src/main.ts
import { createApp } from 'vue'
import { createPinia } from 'pinia'
import App from './App.vue'

const pinia = createPinia()

createApp(App)
  .use(pinia)
  .mount('#app')

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

interface User {
  id: number
  name: string
  email: string
}

// Setup syntax (recommended - like Composition API)
export const useUserStore = defineStore('user', () => {
  // State
  const users = ref<User[]>([])
  const loading = ref(false)
  const error = ref<string | null>(null)

  // Getters (computed)
  const userCount = computed(() => users.value.length)
  const userNames = computed(() => users.value.map(u => u.name))

  // Actions
  async function fetchUsers() {
    loading.value = true
    error.value = null
    try {
      const response = await fetch('/api/users')
      if (!response.ok) throw new Error('Failed to fetch users')
      users.value = await response.json()
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Unknown error'
    } finally {
      loading.value = false
    }
  }

  async function addUser(user: Omit<User, 'id'>) {
    const response = await fetch('/api/users', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(user)
    })
    const newUser = await response.json()
    users.value.push(newUser)
  }

  async function deleteUser(id: number) {
    await fetch(`/api/users/${id}`, { method: 'DELETE' })
    users.value = users.value.filter(u => u.id !== id)
  }

  function $reset() {
    users.value = []
    loading.value = false
    error.value = null
  }

  return {
    // State
    users,
    loading,
    error,
    // Getters
    userCount,
    userNames,
    // Actions
    fetchUsers,
    addUser,
    deleteUser,
    $reset
  }
})

// src/stores/counter.ts
import { defineStore } from 'pinia'

export const useCounterStore = defineStore('counter', {
  state: () => ({
    count: 0,
    name: 'Counter'
  }),

  getters: {
    doubleCount: (state) => state.count * 2,

    // Access other getters
    displayText(): string {
      return `${this.name}: ${this.doubleCount}`
    }
  },

  actions: {
    increment() {
      this.count++
    },

    async incrementAsync() {
      await new Promise(resolve => setTimeout(resolve, 1000))
      this.count++
    }
  }
})

<script setup lang="ts">
import { onMounted } from 'vue'
import { useUserStore } from '@/stores/user'
import { storeToRefs } from 'pinia'

const userStore = useUserStore()

// Extract reactive state (use storeToRefs to maintain reactivity)
const { users, loading, error, userCount } = storeToRefs(userStore)

// Actions don't need storeToRefs
const { fetchUsers, addUser, deleteUser } = userStore

onMounted(() => {
  fetchUsers()
})

async function handleAddUser() {
  await addUser({ name: 'New User', email: '[email protected]' })
}
</script>

<template>
  <div>
    <h1>Users ({{ userCount }})</h1>

    <button @click="handleAddUser">Add User</button>

    <div v-if="loading">Loading...</div>
    <div v-else-if="error">Error: {{ error }}</div>
    <ul v-else>
      <li v-for="user in users" :key="user.id">
        {{ user.name }}
        <button @click="deleteUser(user.id)">Delete</button>
      </li>
    </ul>
  </div>
</template>

// src/stores/auth.ts
import { defineStore } from 'pinia'
import { ref } from 'vue'
import { useUserStore } from './user'

export const useAuthStore = defineStore('auth', () => {
  const token = ref<string | null>(localStorage.getItem('token'))
  const isAuthenticated = computed(() => !!token.value)

  // Use another store
  const userStore = useUserStore()

  async function login(email: string, password: string) {
    const res = await fetch('/api/auth/login', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ email, password })
    })
    const data = await res.json()
    token.value = data.token
    localStorage.setItem('token', data.token)

    // Fetch user data after login
    await userStore.fetchUsers()
  }

  function logout() {
    token.value = null
    localStorage.removeItem('token')
    userStore.$reset()
  }

  return { token, isAuthenticated, login, logout }
})

<!-- UserCard.vue -->
<template>
  <div class="user-card">
    <h3>{{ user.name }}</h3>
    <p>{{ user.email }}</p>
    <button @click="handleEdit">Edit</button>
    <button @click="handleDelete">Delete</button>
  </div>
</template>

<script setup lang="ts">
interface User {
  id: number
  name: string
  email: string
}

// Define props with TypeScript
interface Props {
  user: User
  editable?: boolean
}

const props = withDefaults(defineProps<Props>(), {
  editable: true
})

// Define emits with TypeScript
const emit = defineEmits<{
  edit: [user: User]
  delete: [id: number]
}>()

function handleEdit() {
  if (props.editable) {
    emit('edit', props.user)
  }
}

function handleDelete() {
  emit('delete', props.user.id)
}
</script>

<!-- Parent component -->
<template>
  <UserCard
    :user="user"
    :editable="true"
    @edit="handleEdit"
    @delete="handleDelete"
  />
</template>

<script setup lang="ts">
import UserCard from '@/components/UserCard.vue'

function handleEdit(user: User) {
  console.log('Editing user:', user)
}

function handleDelete(id: number) {
  console.log('Deleting user:', id)
}
</script>

<!-- Card.vue - Reusable card component -->
<template>
  <div class="card">
    <header v-if="$slots.header" class="card-header">
      <slot name="header" />
    </header>

    <div class="card-body">
      <slot />  <!-- Default slot -->
    </div>

    <footer v-if="$slots.footer" class="card-footer">
      <slot name="footer" />
    </footer>
  </div>
</template>

<!-- Usage -->
<template>
  <Card>
    <template #header>
      <h2>User Profile</h2>
    </template>

    <!-- Default slot content -->
    <p>Name: {{ user.name }}</p>
    <p>Email: {{ user.email }}</p>

    <template #footer>
      <button>Edit</button>
      <button>Delete</button>
    </template>
  </Card>
</template>

<!-- List.vue - Generic list component -->
<template>
  <ul>
    <li v-for="(item, index) in items" :key="index">
      <!-- Expose item data to parent -->
      <slot :item="item" :index="index" />
    </li>
  </ul>
</template>

<script setup lang="ts">
interface Props<T> {
  items: T[]
}

defineProps<Props<any>>()
</script>

<!-- Usage -->
<template>
  <List :items="users">
    <template #default="{ item, index }">
      <strong>{{ index + 1 }}.</strong> {{ item.name }} ({{ item.email }})
    </template>
  </List>
</template>

<!-- CustomInput.vue -->
<template>
  <input
    :value="modelValue"
    @input="$emit('update:modelValue', ($event.target as HTMLInputElement).value)"
  />
</template>

<script setup lang="ts">
defineProps<{
  modelValue: string
}>()

defineEmits<{
  'update:modelValue': [value: string]
}>()
</script>

<!-- Usage (syntactic sugar for :modelValue + @update:modelValue) -->
<template>
  <CustomInput v-model="text" />
  <p>{{ text }}</p>
</template>

<script setup lang="ts">
const text = ref('')
</script>

<!-- UserForm.vue -->
<template>
  <div>
    <input :value="name" @input="$emit('update:name', $event.target.value)" />
    <input :value="email" @input="$emit('update:email', $event.target.value)" />
  </div>
</template>

<script setup lang="ts">
defineProps<{
  name: string
  email: string
}>()

defineEmits<{
  'update:name': [value: string]
  'update:email': [value: string]
}>()
</script>