Object.groupBy now builds its result record with a null prototype,
stored as a flag on the record's overflow map. Inspection prints
"[Object: null prototype]", Object.getPrototypeOf answers null, `in`
finds no inherited names, and String(), template literals, toString(),
hasOwnProperty() and propertyIsEnumerable() throw Node's TypeErrors.
Spread copies and structuredClone keep Object.prototype, as in Node.
Index-signature records converted from an Object.create(null) value
keep the null prototype too.
- JavaScript calls of Promise.withResolvers' resolve/reject through the
record no longer fail with an internal compiler error.
- new RegExp with the d or v flag is refused (SC1120) for literal flags
and throws a named error for computed flags, instead of SyntaxError.
- JavaScript .groups reads on matches whose regex is not traceable are
refused like TypeScript's, instead of reading undefined.
- Iterator helpers on the string iterator are refused instead of
failing at run time.
node:test changes, matching Node 24.22:
- { concurrency } on describe, suite, test, it and t.test sets how many
subtests run at once: a number, true for os.availableParallelism() - 1,
or false for 1. Subtests inherit the parent's value.
- Above 1, each subtest runs on its own fiber. Subtests start in
declaration order as slots free up, and t.test and test() calls inside a
concurrent test start the subtest at once; t.test's promise settles when
it finishes. The parent finishes after all of them.
- Results, diagnostics and failures are reported in declaration order.
- A concurrent subtest waits after its beforeEach hooks, and a concurrent
suite before its children, for as many turns as Node's runner does, so
sibling bodies interleave as they do there.
- A concurrency that is not an integer from 1 to 4294967295 throws Node's
ERR_OUT_OF_RANGE RangeError when the test or suite is created.
- Nested test() calls and hooks inside a concurrent subtest attach to the
subtest that runs on the calling fiber.
The concurrency fixture compares the reporter output, the order of the
bodies' side effects, and the range errors with Node, plain and with
SCRIPTC_SAN=1.
promisify(zlib.deflate) and the other callback one-shots (inflate,
deflateRaw, inflateRaw, gzip, gunzip, unzip) over a named or namespace
import of node:zlib now lower. A call through the binding,
gzipAsync(data, options?), runs the callback form's work on the worker
pool and returns a promise that settles where the callback would run:
fulfilled with the Buffer, or rejected with the callback form's Error
(errno, code and message). An invalid option or input rejects the promise
instead of throwing, as the throw inside Node's promisify wrapper does.
The runtime adds scr_zlib_codec_promise and its checked-dynamic twin,
which share the callback forms' options ladder and worker-pool operation
and settle a pending promise in place of the callback. The fallback
declarations gain the matching util.promisify overload.
Node's util.promisify returns the custom promisified forms of
stream.finished and stream.pipeline, which are stream/promises' functions
of the same name. A const binding of promisify over the node:stream named
imports or namespace members now registers that stream/promises member
as the projection, so calls through the binding lower as the
stream/promises call and accept the stream arguments and options it
accepts.
The fallback declarations gain the matching util.promisify overloads.
pipeline's overload comes first: its (...streams: unknown[]) => unknown
type is assignable to every other target's parameter type.
The ESNext array lib is now part of the type world, and Array.fromAsync(source,
mapFn?) compiles when the source is an array of values or of promises. Each
call lowers to an async helper with the spec's loop: elements are awaited
through the async-from-sync iterator, with the same microtask turns as a
`for await` loop over an array, and a mapping function's result is awaited
before it is stored. A throwing or rejecting mapping function and a rejected
element close the iterator before the returned promise rejects, on the turn
Node rejects it. Async generator sources, a thisArg, and arrays that mix
values and promises are refused.
`using` and `await using` now accept object literals and other values typed
Disposable, AsyncDisposable or unknown. The declaration reads the value's
[Symbol.dispose] method ([Symbol.asyncDispose] first for `await using`) and
throws Node's TypeErrors for values that are not objects and for missing or
non-callable methods; null and undefined dispose nothing. Scope exit calls the
method with the value as `this`, and `await using` awaits the result of an
async method but not of the sync fallback. A class instance reached through
such a value throws an SC2020 error, because its dynamic view has no methods.
SuppressedError is its own error class: a failing disposal over a pending
error throws one whose `error` is the disposal error and whose `suppressed` is
the pending error, both non-enumerable as in Node. `new SuppressedError(error,
suppressed, message?)` and `instanceof SuppressedError` compile, and
`extends SuppressedError` is refused.
std::filesystem::copy_file reports a destination that exists but is not
a regular file as invalid_argument in libstdc++ and as not_supported in
libc++, which Node's macOS builds use. cpSync on Apple platforms now
throws ENOTSUP there, as Node does, and the fs errno names include
ENOTSUP.
Corpus 5571 copies a 400-level directory chain instead of 1500 levels,
so its deepest path stays under macOS's 1024-byte PATH_MAX.
5628-promisify-timers.ts compared a 1 ms timer with an immediate armed
at the same time. Their order depends on how much time has passed when
the loop reaches its timers phase: once the delay has elapsed, the timer
fires before the check phase. Node prints either order under load. The
test now orders three timers armed together (1, 10 and 30 ms), which
settle in deadline order. The node-types fixture does the same with two
timers.
fs.cpSync, fs.cp and fs/promises cp compile with every option:
dereference, errorOnExist, filter, force, mode, preserveTimestamps,
recursive and verbatimSymlinks. They follow Node's two implementations.
cpSync follows cp-sync.js over the fs binding: copy errors are plain
Errors with a code, std::error_code failures throw an ErrnoException,
and links inside a copied directory point at their canonical targets.
fs.cp and fs/promises cp follow cp.js, whose copy errors are
SystemErrors with code, info, errno, syscall and path.
Options and paths validate in Node's order with Node's errors. filter
runs for the top-level paths and each entry in Node's order; an async
filter must return a promise that is already settled, and a pending one
throws SC2020. The callback and promise forms complete the copy before
the callback runs or the promise settles. Windows builds throw SC2020.
The copy lives in the new scr_fs_cp.c. Directory walks keep their frames
on the heap, so deep trees also copy on a fiber's stack. File contents
copy with sendfile on Linux, and COPYFILE_FICLONE uses FICLONE
where it exists. ScrError gains the SystemError context and the
ErrnoException key order, with matching fields in the compiler's Error
layout. The stored fs.cp callback uses the same implementation.
Corpus 5567-5571 cover the sync, callback and promise forms, errors,
symlinks and 1500-level trees.
union, intersection, difference, symmetricDifference, isSubsetOf,
isSupersetOf and isDisjointFrom now compile with a Map argument whose key type
is the Set's element type, as well as with a Set. A Map's set record reads its
keys, and its size, has and keys are the builtins, so the helper loops walk
and test the Map's keys in the order the spec gives. Other set-like arguments
are still refused.
The URL host parser kept a host whose last label is a number as a
domain, so new URL("http://127.1").hostname was "127.1" where Node
answers 127.0.0.1, and hosts such as 1.2.3.256, 0x100000000 and
1.2.3.4.5 parsed where Node throws Invalid URL.
A special-scheme host (file: included) that ends in a number now goes
through the WHATWG IPv4 parser: up to four labels after one trailing
empty label, each a decimal, 0x hexadecimal or leading-zero octal
number, every label but the last at most 255 and the last below
256^(5 - labels). The address serializes as dotted decimal, and any
failure makes the URL invalid. The constructor, URL.parse, URL.canParse,
the host and hostname setters and domainToASCII/domainToUnicode share
the parser. Non-special schemes keep their opaque host as written.
Corpus 5860 covers each form.
Node's util.promisify returns the custom promisified form of setTimeout
and setImmediate, which is timers/promises' function of the same name.
A const binding of promisify over the global functions, the node:timers
named imports or the node:timers namespace members now registers that
timers/promises member as the projection, so calls through the binding
lower as the timers/promises call: they fulfill with the given value
(undefined without one) after the delay or in the check phase.
The fallback declarations gain the matching util.promisify overloads.
exec(command, callback) and exec(command, { encoding, maxBuffer },
callback) lower like execFile's callback slice. The command line runs
with /bin/sh -c, as execSync runs it, the call returns the live
ChildProcess, and the error-first callback receives the captured utf8
stdout and stderr. A non-zero exit, including the shell's 127 for a
missing command, reports Node's "Command failed: <command>\n<stderr>":
scr_exec_file takes a shell flag so the message shows the command line.
Under @types/node, child_process.ExecException maps to Error, as
ExecFileException does. Its code member is the child's numeric exit
status, which the runtime error's string code slot does not hold, so
reading it, testing it with `in`, or testing its typeof is a named
refusal.
A boxed function converts its result to dyn, which boxes any promise the
result type holds. The feature scan checked only for a result that is
itself a promise, so boxing a function returning `Promise<T> | undefined`,
a record with an async function field, or an array of async functions
still failed to link with an undefined scr_dyn_new_promise_adapting. The
scan now walks the result type like the other boxed types.
Corpus program 5812 and the runtime-features unit test cover these
results.
The cases were [label, run] tuples in an array, which JavaScript inference
types as (string | (() => void))[]. console.log(label, ...) then received a
union that includes a function value, so coverage counted two statements as
runtime fences. Each case now calls attempt(label, run) directly; the
output is unchanged.
scr_dyn_from_iterator answered kind 0 (not iterable) when reading
Symbol.asyncIterator or Symbol.iterator threw, so Readable.from raised
ERR_INVALID_ARG_TYPE in place of the getter's error. It now answers
kind -1 with the error pending, as its declaration states, and
Readable.from throws the getter's error, as Node does. Corpus 5614 covers
a throwing Symbol.iterator getter and a throwing Symbol.asyncIterator
getter.
SC6001 only looked at call arguments and typed initializers, and only at
strict field subsets: a target that adds optional properties, the empty
record type, `r as T`, a later `v = r` into a typed binding, and records
stored as elements of a typed array literal copied silently.
The scan now reports a copy whenever the property sets differ, covers
those sites, and reports a class instance that reaches a plain record
type which does not keep its identity (the remaining boundary: interfaces
of only generic methods). Every corpus program still reports no
divergence.
Chris Tate