Why am I getting content and parts after updating?

[Godrules500]

After updating to the latest vercel ai sdk version, why do I now get content and parts?

[lgrammel]

content is there for legacy reasons. we are in the process of changing ui messages to parts, which can support richer information like reasoning, sources, custom data etc.

[lgrammel]

It should be resilient to missing parts. I'll look into it.

[Jaikant]

@lgrammel in my test, I was noticing that while content contains the full message, parts only contains the first word. Below an example. Is this because the functionality is under development?

{
  "id": "1jJwt3n67zDT1rNN",
  "createdAt": "2025-03-04T10:11:03.148Z",
  "role": "assistant",
  "content": "Hello! How can I assist you today? If you have any questions or if you'd like to get in touch with us, please provide your **name, contact number (including the country code), email address,** and **reason for your inquiry.**",
  "parts": [
    {
      "type": "text",
      "text": "Hello"
    }
  ]
}```

[lgrammel]

@Jaikant no. how can i reproduce this? can you file a bug report?

[Jaikant]

I was testing with "@ai-sdk/solid": "^1.1.20" and the code used was as below, I was checking the value based on the console logs printed by the createEffect

import { Component, For, createEffect, createSignal } from 'solid-js';
import { useChat } from '@ai-sdk/solid';

const Chat: Component = () => {
  const [files, setFiles] = createSignal<FileList | undefined>(undefined);
  let fileInputRef: HTMLInputElement | undefined;

  const {
    messages,
    input,
    handleInputChange,
    handleSubmit,
    isLoading,
  } = useChat({
    api: 'http://localhost:8001/stream',
    streamProtocol: 'text',
    experimental_prepareRequestBody({ messages }) {
      return {
        message: messages[messages.length - 1].content,
        sessionId: '...',
        agentName: "...",
      };
    },
    onResponse: response => {
      console.log('Received HTTP response from server:', response);
    },
  });

  const onSend = async (e: Event) => {
    e.preventDefault();
    handleSubmit(e, {
      experimental_attachments: files(),
    });

    // Reset form
    setFiles(undefined);
    if (fileInputRef) {
      fileInputRef.value = '';
    }
  };

  createEffect(() => {
    const chunks = messages();
    console.log('messages:', chunks);
    chunks.map((chunk, index) => {
      console.log(`message at #${index} is: `, JSON.stringify(chunk));
    });
  });

  return (
    <div class="flex flex-col w-full max-w-md py-24 mx-auto stretch">
      {/* Display each message as it streams in */}
      <For each={messages()}>
      {m => (
          <div class="whitespace-pre-wrap">
            {m.role === 'user' ? 'User: ' : 'AI: '}
            {m.content}
            <div>
              <For each={m.experimental_attachments?.filter(attachment =>
                attachment?.contentType?.startsWith('image/'))}>
                {(attachment, index) => (
                  <img
                    src={attachment.url}
                    width={500}
                    height={500}
                    alt={attachment.name ?? `attachment-${index()}`}
                  />
                )}
              </For>
            </div>
          </div>
        )}
      </For>

      {isLoading() && (
        <div class="mt-4 text-gray-500">
          <div>Loading...</div>
          <button
            type="button"
            class="px-4 py-2 mt-4 text-blue-500 border border-blue-500 rounded-md"
            onClick={stop}
          >
            Stop
          </button>
        </div>
      )}


      {/* Simple input form to send user messages */}
      <form
        onSubmit={onSend}
      >
        <input
          type="file"
          class="w-full"
          onChange={(e) => setFiles(e.currentTarget.files ?? undefined)}
          multiple
          ref={fileInputRef}
        />
        <input
          type="text"
          value={input()}
          onInput={handleInputChange}
          placeholder="Type a message..."
        />
        <button
          type="submit"
          class="w-full p-2 bg-blue-500 text-white rounded"
          disabled={isLoading()}
        >
          Sends
        </button>
      </form>
    </div>
  );
};

export default Chat;

Can I raise a issue (bug) based on the above?

[lgrammel]

@Jaikant yes pls, it's a bug, most likely solid-specific

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