// ❌ v5 (OLD)
{messages.map(m => (
  <div key={m.id}>{m.content}</div>
))}

// ✅ v6 (NEW)
{messages.map(m => (
  <div key={m.id}>
    {m.parts.map((part, i) => {
      if (part.type === 'text') return <span key={i}>{part.text}</span>;
      if (part.type === 'tool-invocation') return <ToolCall key={i} tool={part} />;
      if (part.type === 'file') return <FilePreview key={i} file={part} />;
      return null;
    })}
  </div>
))}

import { useChat } from '@ai-sdk/react';
import type { InferAgentUIMessage } from 'ai';
import { myAgent } from './agent';

export default function AgentChat() {
  const { messages, sendMessage } = useChat<InferAgentUIMessage<typeof myAgent>>({
    api: '/api/chat',
  });
  // messages are now type-checked against agent schema
}

import { useChat } from '@ai-sdk/react';
import { useState } from 'react';

export default function ChatWithApproval() {
  const { messages, sendMessage, addToolApprovalResponse } = useChat({
    api: '/api/chat',
  });

  const handleApprove = (toolCallId: string) => {
    addToolApprovalResponse({
      toolCallId,
      approved: true,  // or false to deny
    });
  };

  return (
    <div>
      {messages.map(message => (
        <div key={message.id}>
          {message.toolInvocations?.map(tool => (
            tool.state === 'awaiting-approval' && (
              <div key={tool.toolCallId}>
                <p>Approve tool call: {tool.toolName}?</p>
                <button onClick={() => handleApprove(tool.toolCallId)}>
                  Approve
                </button>
                <button onClick={() => addToolApprovalResponse({
                  toolCallId: tool.toolCallId,
                  approved: false
                })}>
                  Deny
                </button>
              </div>
            )
          ))}
        </div>
      ))}
    </div>
  );
}

import { useChat, lastAssistantMessageIsCompleteWithApprovalResponses } from '@ai-sdk/react';

export default function AutoSubmitChat() {
  const { messages, sendMessage } = useChat({
    api: '/api/chat',
    sendAutomaticallyWhen: lastAssistantMessageIsCompleteWithApprovalResponses,
    // Automatically resubmit after all approval responses provided
  });
}

import { useChat } from '@ai-sdk/react';
import { z } from 'zod';

const schema = z.object({
  summary: z.string(),
  sentiment: z.enum(['positive', 'neutral', 'negative']),
});

export default function StructuredChat() {
  const { messages, sendMessage } = useChat({
    api: '/api/chat',
    // Server can now stream structured output with chat messages
  });
}

const { messages, input, handleInputChange, handleSubmit, append } = useChat();

<form onSubmit={handleSubmit}>
  <input value={input} onChange={handleInputChange} />
</form>

const { messages, sendMessage } = useChat();
const [input, setInput] = useState('');

<form onSubmit={(e) => {
  e.preventDefault();
  sendMessage({ content: input });
  setInput('');
}}>
  <input value={input} onChange={(e) => setInput(e.target.value)} />
</form>

import { useAssistant } from '@ai-sdk/react';

'use client';
import { useAssistant } from '@ai-sdk/react';
import { useState, FormEvent } from 'react';

export default function AssistantChat() {
  const { messages, sendMessage, isLoading, error } = useAssistant({
    api: '/api/assistant',
  });
  const [input, setInput] = useState('');

  const handleSubmit = (e: FormEvent) => {
    e.preventDefault();
    sendMessage({ content: input });
    setInput('');
  };

  return (
    <div>
      {messages.map(m => (
        <div key={m.id}>
          <strong>{m.role}:</strong> {m.content}
        </div>
      ))}
      <form onSubmit={handleSubmit}>
        <input
          value={input}
          onChange={(e) => setInput(e.target.value)}
          disabled={isLoading}
        />
      </form>
      {error && <div>{error.message}</div>}
    </div>
  );
}

// ✅ CORRECT
return result.toDataStreamResponse();

// ❌ WRONG
return new Response(result.textStream);

// App Router - use toDataStreamResponse()
export async function POST(req: Request) {
  const result = streamText({ /* ... */ });
  return result.toDataStreamResponse(); // ✅
}

// Pages Router - use pipeDataStreamToResponse()
export default async function handler(req, res) {
  const result = streamText({ /* ... */ });
  return result.pipeDataStreamToResponse(res); // ✅
}

// ❌ WRONG - body captured once
const { userId } = useUser();
const { messages } = useChat({
  body: { userId },  // Stale!
});

// ✅ CORRECT - use controlled mode
const { userId } = useUser();
const { messages, sendMessage } = useChat();

sendMessage({
  content: input,
  data: { userId },  // Fresh on each send
});

// ❌ WRONG
useEffect(() => {
  saveMessages(messages);
}, [messages, saveMessages]); // saveMessages triggers re-render!

// ✅ CORRECT
useEffect(() => {
  saveMessages(messages);
}, [messages]); // Only depend on messages

// ✅ GOOD - Streaming (shows tokens as they arrive)
const { messages } = useChat({ api: '/api/chat' });

// ❌ BAD - Non-streaming (user waits for full response)
const response = await fetch('/api/chat', { method: 'POST' });

{isLoading && <div>AI is typing...</div>}

{isLoading && <button onClick={stop}>Stop</button>}

useEffect(() => {
  messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
}, [messages]);

<input disabled={isLoading} />

'use client';
import { useChat } from '@ai-sdk/react';
import { useEffect } from 'react';

export default function Chat() {
  const { messages, sendMessage, resumeStream } = useChat({
    api: '/api/chat',
    resume: true,
  });

  useEffect(() => {
    // ❌ Triggers twice in strict mode → two concurrent streams
    sendMessage({ content: 'Hello' });
    // or
    resumeStream();
  }, []);
}

// ✅ Use ref to track execution
import { useRef } from 'react';

const hasSentRef = useRef(false);

useEffect(() => {
  if (hasSentRef.current) return;
  hasSentRef.current = true;

  sendMessage({ content: 'Hello' });
}, []);

// For resumeStream specifically:
const hasResumedRef = useRef(false);

useEffect(() => {
  if (!autoResume || hasResumedRef.current || status === 'streaming') return;
  hasResumedRef.current = true;
  resumeStream();
}, [autoResume, resumeStream, status]);

{
  "dependencies": {
    "ai": "^6.0.8",
    "@ai-sdk/react": "^3.0.6",
    "@ai-sdk/openai": "^3.0.2",
    "react": "^18.3.0",
    "zod": "^3.24.2"
  }
}

{
  "dependencies": {
    "ai": "^5.0.99",
    "@ai-sdk/react": "^1.0.0",
    "@ai-sdk/openai": "^2.0.68"
  }
}