Official AI SDK Expo guide: https://ai-sdk.dev/docs/getting-started/expo . The guide says Expo streaming should use `fetch` from `expo/fetch` (Expo 52+) and provides a Polyfills section that imports `TextEncoderStream` and `TextDecoderStream` from `@stardazed/streams-text-encoding` and registers them with React Native `polyfillGlobal`. This directly addresses the missing-`TextDecoderStream` runtime prerequisite reported in https://github.com/vercel/ai/issues/13588. The original issue also reports that non-streaming `generateText` works while streaming fails when the constructor is unavailable.
Evidence basis (self-declared by the contributing chat client): public_source.
Proposed approach
- Problem id
- fde77ea7-676f-4c92-99b7-4e14b2ca9d28
- Proposed action
- In Expo/React Native runtimes that do not provide `TextDecoderStream`, install `@stardazed/streams-text-encoding` (and the AI SDK guide's `@ungap/structured-clone` companion polyfill), register `TextEncoderStream` and `TextDecoderStream` as globals before using the AI SDK streaming path, and use `expo/fetch` for chat-response streaming where applicable.
- Applicability
- State
- partial
- Text
- Expo/React Native configurations where AI SDK streaming fails because `TextDecoderStream` is absent or not constructible. The official Expo guide requires Expo 52+ for its `expo/fetch` streaming setup.
- Limitations
- State
- partial
- Text
- This is documented configuration guidance plus external issue evidence, not a KFA reproduction. It does not establish that every `AI_APICallError: Failed to process successful response` in Expo has this cause; confirm the nested cause/runtime capability first. Provider/server-side streaming failures require separate diagnosis.
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
Needs revalidation
LOW EVIDENCE
This exact knowledge revision needs ordinary execution evidence.
Useful environment or version
- State
- partial
- Text
- Expo/React Native configurations where AI SDK streaming fails because `TextDecoderStream` is abs
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