docs: add handling errors for OpenAI provider (vercel#500)

Author: devjiwonchoi

docs/pages/docs/guides/providers/openai.mdx

@@ -152,13 +152,6 @@ export async function POST(req: Request) {
     prompt
   })
 
-  // Check for errors
-  if (!response.ok) {
-    return new Response(await response.text(), {
-      status: response.status
-    })
-  }
-
   // Convert the response into a friendly text-stream
   const stream = OpenAIStream(response)
 
@@ -214,6 +207,47 @@ export default function Completion() {
 
 </Steps>
 
+## Guide: Handling Errors
+
+The OpenAI's API throws an `OpenAI.APIError` when an error occurs during a request. It is recommended to wrap your API calls in a `try/catch` block to handle these errors. For more information about `OpenAI.APIError`, see [OpenAI SDK Handling Errors](https://github.com/openai/openai-node?tab=readme-ov-file#handling-errors).
+
+```tsx filename="app/api/chat/route.ts"
+import OpenAI from 'openai'
+import { OpenAIStream, StreamingTextResponse } from 'ai'
+import { NextResponse } from 'next/server'
+
+const openai = new OpenAI({
+  apiKey: process.env.OPENAI_API_KEY
+})
+
+export const runtime = 'edge'
+
+export async function POST(req: Request) {
+  // Wrap with a try/catch to handle API errors
+  try {
+    const { messages } = await req.json()
+
+    const response = await openai.chat.completions.create({
+      model: 'gpt-3.5-turbo',
+      stream: true,
+      messages
+    })
+
+    const stream = OpenAIStream(response)
+
+    return new StreamingTextResponse(stream)
+  } catch (error) {
+    // Check if the error is an APIError
+    if (error instanceof OpenAI.APIError) {
+      const { name, status, headers, message } = error
+      return NextResponse.json({ name, status, headers, message }, { status })
+    } else {
+      throw error
+    }
+  }
+}
+```
+
 ## Guide: Save to Database After Completion
 
 It’s common to want to save the result of a completion to a database after streaming it back to the user. The `OpenAIStream` adapter accepts a couple of optional callbacks that can be used to do this.