Cleanup of the Bedrock adapter (ba1705d) following parallel review
passes for code reuse, code quality, and efficiency.
- Drop dead `text` join helper and unused `TextPart` import.
- Schema-validate `model.native.aws_credentials` instead of seven
manual `typeof` guards in `credentialsFromInput`. Removes the
unsafe `as Record<string, unknown>` cast and fixes the dead
`native?.region` fallback (the `model()` constructor only writes
`aws_region`).
- Skip the JSON.parse → JSON.stringify → Schema.fromJsonString triple
round-trip in the frame consumer. The eventstream codec already
hands us a UTF-8 payload; parse once and feed the wrapped object
directly to `Schema.decodeUnknownSync(BedrockChunk)`.
- Replace O(n²) buffer concat in `consumeFrames` with a cursor-based
state `{ buffer, offset }`. Compaction happens once per network
chunk via `appendChunk` instead of per frame; frame slicing is
zero-copy via `subarray`. Bounded buffer growth regardless of
stream length.
- Rename `ParserState.finishReason` → `pendingStopReason` (raw
string) and defer the `mapFinishReason` call to the single emit
site, plus the `onHalt` fallback. Tightens the helper's signature
to `(reason: string)` so the chunk-typed `messageStop.stopReason`
flows through without the optional widening.
- Restructure `signRequest` to take an object parameter (was four
positional args), and replace the manual `forEach`-into-record with
`Object.fromEntries(signed.headers.entries())`.
- Inline single-use `status` and `useTools` variables.
- Widen `fixedResponse` to accept `ConstructorParameters<Response>[0]`
so binary fixtures (`Uint8Array`, streams) flow without casts. The
Bedrock test's `fixedBytes` helper now wraps it cleanly.
- Tidy `captureResponseBody` into a ternary returning the union shape
directly so the call site spreads the captured object without
reaching for `bodyEncoding` explicitly.
Verified: `bun typecheck` clean, 106 pass / 0 fail / 0 skip
(unchanged from before the refactor).
Kit Langton
bab2fbc7f6