A record built from unchecked element reads can hold undefined in a field
the checker calls present. Such a record kept its widened layout only in
an inferred binding: an annotated parameter or return, or an unannotated
return, converted it to the declared layout with a checked narrow, which
throws a TypeError for a missing element where Node passes undefined
through.
Record values that flow between bindings and the parameters and results
of functions and methods whose every call is visible now form flow
classes. A class takes the widened layout, with the union of its members'
optional fields, when it is closed: each value entering it is a fresh
object literal or comes from a member, each use of a member reads or
writes its fields, passes it to another member or only inspects it, and
every member declares the same shape. Members then share one layout, so
no conversion runs at the boundary and the record keeps its identity.
A class that reaches other storage keeps the declared layout for every
member, including the inferred bindings and the record parameters the
analysis widened before. Converting there copied the object, so writes
through a parameter or a pushed record did not reach the caller's object;
such a literal now converts once where it is created.
log-lines writes 200k lines (scale 4) through the common console shapes:
a single template literal, string plus number arguments, several
primitive arguments, process.stdout.write chunks, and an occasional
console.error line. The runner captures stdout through a pipe, so the
workload measures immediate per-line writes into a pipe.
The suite only had single-process CPU workloads. Add the two largest
real-world categories:
- http-api (kind "server"): a node:http JSON API in the static subset
(routing, query parsing, seeded catalog, per-cart state, typed JSON
bodies, ETag/If-None-Match, auth and request-id headers), driven by
clients/http-load.mjs, a raw-socket keep-alive HTTP/1.1 load client
that is identical for every server. 64 connections, 2 client threads,
4,000 untimed warmup and 40,000 measured requests on loopback. The
per-connection request schedule is seeded and server state is
partitioned per connection, so the response digest is deterministic.
Correctness compares server stdout, server stderr (minus the PORT
line), exit status, and client stdout with Node byte-for-byte. The
timed sample is the measured-phase wall time; a second table reports
req/s, p50/p90/p99 latency, client CPU, and peak RSS.
- cli-config (process, launches: 20): a deploy-plan CLI that reads a
~110 KB JSON manifest, validates, interpolates env values, and orders
80 services into dependency waves. Each sample is the median of 20
launches, so startup dominates.
The runner stays backward compatible: process workloads behave as
before, the JSON report keeps its fields and adds kind, launches,
category, server, node_peak_rss_bytes, and geomean_vs_node_by_category,
and the summary prints per-category geomeans (cpu, startup, server).
Fourteen application-shaped workloads (JSON, regex, parsing and class
dispatch, sorting, rendering, collection pipelines, async fan-out,
Map/Set graphs, allocation, numeric kernels, exceptions, CSV, and the
two multi-module build benchmark apps on large inputs).
bench:runtime builds each workload with one or two checkouts, refuses to
time any executable whose stdout, stderr, or exit status differs from
Node, interleaves baseline and candidate launches, and reports medians
with bootstrap 95% confidence intervals, binary size, and peak RSS.
Chris Tate