How to make version 4.1 work well with Expo 52 streamProtocol: text?

[jbreite]

I upgraded my SDK to this "ai": "^4.1.16" with "expo": "~52.0.20". I'm using these providers:

    "@ai-sdk/google": "^1.1.8",
    "@ai-sdk/groq": "^1.1.7",
    "@ai-sdk/openai": "^1.1.9",
    "@ai-sdk/react": "^1.1.8",

To get it to work with Expo, I had to do these polyfills, which I didn't have to do before the version update.

import { Platform } from "react-native";

if (Platform.OS !== "web") {
  const setupPolyfills = async () => {
    const { polyfillGlobal } = await import(
      "react-native/Libraries/Utilities/PolyfillFunctions"
    );

    const { TextEncoderStream, TextDecoderStream } = await import(
      "@stardazed/streams-text-encoding"
    );

    polyfillGlobal("TextEncoderStream", () => TextEncoderStream);
    polyfillGlobal("TextDecoderStream", () => TextDecoderStream);
  };

  setupPolyfills();
}

export {};

Additionally, I had to change my useChat to use this streamProtocol: "text". Found this fix from these docs. However, I don't see why I need to do this because I'm not doing any of these things:

This can be caused by using an older version of the AI SDK in the backend, by providing a text stream using a custom provider, or by using a raw LangChain stream result.

My request that is done the same way the Expo docs work on the site where I am using streamText, a google model, and a tool call.

Is there a reason that I still have to use the streamProtocol: "text". I'm confused as to what chnaged into the SDK and why I need it now and have to write extra code to parse the message?

[lgrammel]

No, the streamProtocol: "text" setting should not be required with current AI SDK versions. What happens when you do not use it?

[jbreite]

The structuredClone polyfill fixed it - here!