$ the-wire · showcase
TransformStream construction trimmed, SEA archive mount re-landed
By RepoJournal · Filed · About Node.js · Composed from the cited sources · methodology
Node's webstreams work moves to the cost of constructing a TransformStream, while the SEA vfsArchive change returns with the worker regression fixed and test_runner gains the Jest-style mock shorthands.
stream: trim TransformStream construction costs nodejs/node
Round 22 of the webstreams performance effort targets what a TransformStream costs to construct: profiling showed the creation benchmarks are dominated by the scavenger rather than by JavaScript, because a start step pending in the microtask queue keeps the whole stream graph live across young-generation collections. The takeaway from the profiling is that creation cost follows the bytes each s...
sea: mount vfsArchive at layer 0 and in workers nodejs/node
Re-land of the vfsArchive mount at layer 0, reverted previously after it broke parallel/test-bootstrap-modules under worker mode; the second commit fixes that by recording the answer in C++ as an internal [sea_vfs_archive] option, so workers no longer load internal/vfs/sea and internalBinding('sea') at startup just to ask whether an archive exists.
test_runner: add mock return, resolve, reject and throw shorthands nodejs/node
MockFunctionContext gains mockReturnValue(), mockResolvedValue(), mockRejectedValue() and mockThrownValue() as shorthands for the common mockImplementation() patterns, matching the equivalent Jest and Vitest APIs.
v5.2.0 nodejs/remark-preset-lint-node
v5.2.0 of the docs lint preset lands the alpha-version rule; Node.js 27 introduces Alpha releases versioned as vN.0.0-alpha.X.Y.Z, and REPLACEME placeholders are replaced with the full Alpha version at release time, so the YAML comments in the docs need to accept that shape.
deps: update undici to 8.12.2 nodejs/node
Elsewhere: undici moved to 8.12.2 and the reliability desk filed its report for 2026-10-17.
