fix(ext/web): narrow ReadableStreamBYOBRequest.view to Uint8Array#33477
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The WHATWG Streams spec change at whatwg/streams#1367 specifies that `ReadableStreamBYOBRequest.view` is always a `Uint8Array` (the BYOB controller already constructs it that way internally). Reflect that both in the public type declaration in `lib.deno_web.d.ts` and in the JSDoc on the implementation, narrowing the return type from `ArrayBufferView | null` to `Uint8Array<ArrayBuffer> | null`. Fixes denoland#33476.
bartlomieju
approved these changes
Apr 25, 2026
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Summary
Per the spec change at whatwg/streams#1367,
ReadableStreamBYOBRequest.viewis always aUint8Array— the BYOB controller already constructs it that way internally. Narrow the public type fromArrayBufferView | nulltoUint8Array<ArrayBuffer> | null:cli/tsc/dts/lib.deno_web.d.ts— the user-facing TypeScript declaration.ext/web/06_streams.js— JSDoc on both the internal[_view]slot and theviewgetter.Before this PR, code like
const v: Uint8Array = req.view!failed type-checking with TS2740 againstArrayBufferView<ArrayBufferLike>. After, it compiles and rejects assignment to incompatible views (e.g.DataView) with a meaningful TS2322.Fixes #33476.
Test plan
tests/unit/streams_test.ts(ReadableStreamBYOBRequest.view is a Uint8Array) that:const view: Uint8Array<ArrayBuffer> | null = byobReq.view;assignment that compile-fails without the fix and compiles with it,instanceof Uint8Arrayand that writes through it round-trip back to the BYOB reader../x buildclean;./x fmtclean;./x lintclean.