James M Snell

Consolidated IdentityTransformStream/FixedLengthStream Test Suite A structured, consolidated suite for ITS/FLS. Runs both the legacy C++ and TypeScript implementations across a common set of tests, with additional tests for unflagged legacy behaviors. Accomodation for intentional divergences between the implementations is called out with two open TODOs for bugs to fix in the TS impl.

Add digest streams suite; migrate existing DigestStream tests

Implement TS DigestStream DigestStream is one of only two WritableStream subclasses in the runtime. When the typescript_implemented_streams flag swaps globalThis.WritableStream for the TypeScript class, a C++ subclass of the C++ WritableStream stops passing the brand checks pipeTo relies on, and instanceof WritableStream becomes false for it. Reimplementing the subclass in TypeScript is what restores the hierarchy. Only the stream semantics move. Hashing stays in C++ behind a new DigestContextHandle, reached through a deliberately crypto-free declaration in digest-bootstrap.h so the per-isolate bootstrap need not depend on the crypto headers. String chunks are forwarded to it rather than encoded here, because the encoding is not expressible in JavaScript: TextEncoder always substitutes U+FFFD, so it cannot produce the WTF-8 bytes DigestStream has always hashed. That is also why update() returns a byte count, a string's UTF-8 length not being observable from JavaScript. Both implementations run crypto-streams-test.js unmodified so the two cannot drift. ts-digest-stream-test.js covers TypeScript-only behavior and holds the canary that the install in main.ts actually took effect, without which the rest of the suite would pass against the C++ class too. One divergence is intentional: the digest promise is marked handled, so abandoning it produces no unhandled-rejection report where the C++ implementation does. Consuming digest is optional, an abort still surfaces through the writer's ready/closed promises, and marking does not propagate to derived promises. The other subclass, FileSystemWritableFileStream, has the same problem but is constructed from C++ rather than by user code, so it needs a native source/sink bridge instead of a straight port.

Add readable streams suite: scaffold and core modules (phase A)

Add compression streams suite; migrate existing CS/DS tests

Add cache, htmlrewriter, and formdata streams suites

Add piping suite: migrate pipe matrix (phase A)

Add writable streams suite; migrate existing WritableStream tests

Streams suites: data-volume coverage (small through very large transfers)

More JsReadableStream/JsWritableStream work (#7029)