docs: document useChat() from Vercel AI SDK

docs/content/1.docs/2.features/ai.md

@@ -151,5 +151,81 @@ export default defineEventHandler(async () => {
 
 Explore open source templates made by the community:
 
-- [Atidraw](https://github.com/atinux/atidraw): leverage AI to generate the alt text of the user drawing and generate an alternative image with AI ([blog post](/blog/cloudflare-ai-for-user-experience)).
-- [Hub Chat](https://github.com/ra-jeev/hub-chat): a chat interface to interact with various text generation AI models ([blog post](https://rajeev.dev/create-cloudflare-workers-ai-llm-playground-using-nuxthub-and-nuxtui)).
+::card-group
+  ::card{title="Atidraw" to="https://github.com/atinux/atidraw"}
+  Generate the alt text of the user drawing and generate an alternative image with AI.
+  ::
+  ::card{title="Hub Chat" to="https://github.com/ra-jeev/hub-chat"}
+  A chat interface to interact with various text generation AI models.
+  ::
+::
+
+## Vercel AI SDK
+
+It is possible to use the Vercel AI SDK with Cloudflare Workers AI.
+
+NuxtHub AI is compatible with some functions of the  [Vercel AI SDK](https://sdk.vercel.ai), which enables streaming responses.
+
+Make sure to install the Vercel AI SDK in your project.
+
+```[Terminal]
+npx nypm add ai @ai-sdk/vue
+```
+
+::note
+[`nypm`](https://github.com/unjs/nypm) will detect your package manager and install the dependencies with it.
+::
+
+### `useChat()`
+
+To leverage the `useChat()` Vue composable, you need to create a `POST /api/chat` endpoint that uses the `hubAI()` server composable and returns a compatible stream for the Vercel AI SDK.
+
+```ts [server/api/chat.post.ts]
+import { AIStream, formatStreamPart } from 'ai'
+
+export default defineEventHandler(async (event) => {
+  const { messages } = await readBody(event)
+
+  const stream = await hubAI().run('@cf/meta/llama-3.1-8b-instruct', {
+    messages,
+    stream: true
+  }) as ReadableStream
+
+  // Return a compatible stream for the Vercel AI SDK
+  return AIStream(
+    new Response(stream),
+    data => formatStreamPart('text', JSON.parse(data).response)
+  )
+})
+```
+
+Then, we can create a chat component that uses the `useChat()` composable.
+
+```vue [app/pages/chat.vue]
+<script setup lang="ts">
+import { useChat } from '@ai-sdk/vue'
+
+const { messages, input, handleSubmit, isLoading, stop, error, reload } = useChat()
+</script>
+
+<template>
+  <div v-for="m in messages" :key="m.id">
+    {{ m.role }}: {{ m.content }}
+  </div>
+  <div v-if="error">
+    <div>{{ error.message || 'An error occurred' }}</div>
+    <button @click="reload">retry</button>
+  </div>
+  <form @submit="handleSubmit">
+    <input v-model="input" placeholder="Type here..." />
+    <button v-if="isLoading" @click="stop">stop</button>
+    <button v-else type="submit">send</button>
+  </form>
+</template>
+```
+
+Learn more about the [`useChat()` Vue composable](https://sdk.vercel.ai/docs/reference/ai-sdk-ui/use-chat).
+
+::callout
+Check out our [`pages/ai.vue` full example](https://github.com/nuxt-hub/core/blob/main/playground/app/pages/ai.vue) with Nuxt UI & Nuxt MDC.
+::

playground/app/pages/ai.vue

@@ -1,93 +1,34 @@
 <script setup lang="ts">
-import destr from 'destr'
+import { useChat } from '@ai-sdk/vue'
 
-interface Message {
-  role: 'ai' | 'user'
-  message: string
-}
-
-const prompt = ref('')
-const loading = ref(false)
-const messages = ref<Message[]>([])
-const currentAIResponse = ref('')
-
-async function sendPrompt() {
-  if (loading.value) return
-  loading.value = true
-  currentAIResponse.value = ''
-  messages.value.push({
-    role: 'user',
-    message: prompt.value
-  })
-  const promptToSend = prompt.value
-  prompt.value = ''
-  const body = await $fetch('/api/ai', {
-    method: 'POST',
-    responseType: 'stream',
-    body: {
-      prompt: promptToSend
-    }
-  })
-  const reader = body.getReader()
-  const decoder = new TextDecoder()
-  let result = await reader.read()
-  while (!result.done) {
-    const text = decoder.decode(result.value)
-    for (const line of text.split('\n')) {
-      if (!line) continue
-      const data: any = destr(line.replace('data: ', '')) || {}
-      if (data?.response) {
-        currentAIResponse.value += data.response
-      }
-    }
-    result = await reader.read()
-  }
-  messages.value.push({
-    role: 'ai',
-    message: currentAIResponse.value
-  })
-  currentAIResponse.value = ''
-  loading.value = false
-}
+const { messages, input, handleSubmit, isLoading, stop, error, reload } = useChat()
 </script>
 
 <template>
   <UCard>
-    <div class="h-full overflow-auto chat-messages">
-      <div v-for="(message, i) in messages" :key="i" class="flex flex-col p-4">
-        <div v-if="message.role === 'ai'" class="pr-8 mr-auto">
-          <div class="p-2 mt-1 text-sm text-gray-700 bg-gray-200 rounded-lg text-smp-2 whitespace-pre-line">
-            {{ message.message }}
-          </div>
-        </div>
-        <div v-else class="pl-8 ml-auto">
-          <div class="p-2 mt-1 text-sm text-white bg-blue-400 rounded-lg whitespace-pre-line">
-            {{ message.message }}
-          </div>
+    <div class="h-full overflow-auto">
+      <div v-for="message in messages" :key="message.id" class="flex flex-col p-4">
+        <div :class="message.role === 'assistant' ? 'pr-8 mr-auto' : 'pl-8 ml-auto'">
+          <MDC
+            class="p-2 mt-1 text-sm rounded-lg text-smp-2 whitespace-pre-line"
+            :class="message.role === 'assistant' ? 'text-white bg-blue-400' : 'text-gray-700 bg-gray-200'"
+            :value="message.content"
+          />
         </div>
       </div>
-      <div v-if="currentAIResponse" class="flex flex-col p-4">
-        <div class="pr-8 mr-auto">
-          <div class="p-2 mt-1 text-sm text-gray-700 bg-gray-200 rounded-lg text-smp-2 whitespace-pre-line">
-            {{ currentAIResponse }}
-          </div>
+      <div v-if="error" class="flex items-center justify-center gap-2">
+        <div class="text-red-500">
+          {{ 'An error occurred' }}
         </div>
+        <UButton color="gray" size="xs" @click="reload">
+          retry
+        </UButton>
       </div>
     </div>
-    <form class="flex items-center w-full p-2 gap-2" @submit.prevent="sendPrompt">
-      <UInput
-        v-model="prompt"
-        type="text"
-        placeholder="Type here..."
-        class="w-full"
-        :disabled="loading"
-      />
-      <UButton
-        :loading="loading"
-        icon="i-heroicons-paper-airplane"
-        type="submit"
-        color="black"
-      />
+    <form class="flex items-center w-full p-2 gap-2" @submit.prevent="handleSubmit">
+      <UInput v-model="input" placeholder="Type here..." class="w-full" :disabled="Boolean(error)" />
+      <UButton v-if="isLoading" icon="i-heroicons-stop" color="black" @click="stop" />
+      <UButton v-else icon="i-heroicons-paper-airplane" type="submit" color="black" />
     </form>
   </UCard>
 </template>

playground/nuxt.config.ts

@@ -7,6 +7,7 @@ export default defineNuxtConfig({
 
   modules: [
     '@nuxt/ui',
+    '@nuxtjs/mdc',
     '@kgierke/nuxt-basic-auth',
     module
   ],
@@ -20,7 +21,7 @@ export default defineNuxtConfig({
     bindings: {
       // Used for /api/hyperdrive
       hyperdrive: {
-        POSTGRES: '08f7bc805d1d409aac17e72af502abd0'
+        POSTGRES: '8bb2913857b84c939cd908740fa5a5d5'
       }
     }
     // projectUrl: ({ branch }) => branch === 'main' ? 'https://playground.nuxt.dev' : `https://${encodeHost(branch).replace(/\//g, '-')}.playground-to39.pages.dev`

playground/package.json

@@ -8,10 +8,13 @@
     "preview": "nuxi preview"
   },
   "dependencies": {
+    "@ai-sdk/vue": "^0.0.45",
     "@iconify-json/simple-icons": "^1.1.114",
     "@kgierke/nuxt-basic-auth": "^1.6.0",
     "@nuxt/ui": "^2.18.4",
     "@nuxthub/core": "latest",
+    "@nuxtjs/mdc": "^0.8.3",
+    "ai": "^3.3.21",
     "drizzle-orm": "^0.33.0",
     "nuxt": "^3.13.0",
     "postgres": "^3.4.4"

playground/server/api/chat.post.ts

@@ -0,0 +1,20 @@
+import { AIStream, formatStreamPart } from 'ai'
+
+export default defineEventHandler(async (event) => {
+  const { messages } = await readBody(event)
+
+  const stream = await hubAI().run('@cf/meta/llama-3.1-8b-instruct', {
+    messages,
+    stream: true
+  }) as ReadableStream
+
+  // For testing purposes, we'll randomly throw an error
+  // if (Math.round(Math.random()) === 1) {
+  //   throw createError({
+  //     status: 500,
+  //     statusMessage: 'Nope'
+  //   })
+  // }
+
+  return AIStream(new Response(stream), data => formatStreamPart('text', JSON.parse(data).response))
+})