- node:punycode: encode, decode, toASCII, toUnicode, ucs2.decode,
ucs2.encode and version, ported from the punycode.js 2.1.0 Node bundles
(scr_url.c), with its RangeErrors. DEP0040 follows Node: a static ES
import reports before any module evaluates and before the program can
register a 'warning' listener; require() reports on the next tick, once
for both spellings, not when a dependency under node_modules loads the
module first, and not under process.noDeprecation.
- node:constants: the frozen object Node builds from os.constants'
dlopen, errno, priority and signals groups, fs.constants (node_constants.cc
order and guards) and crypto.constants (scr_os.c); its bindings read it as
a checked-dynamic value.
These unblock tr46 (whatwg-url, node-fetch@2) and graceful-fs (fs-extra).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- The EventEmitter leak warning reaches process 'warning' listeners on the next tick
- The events listener-count and max-listener helpers work over EventEmitter instances
- timers/promises setTimeout, setImmediate and scheduler.wait accept an AbortSignal
- timers/promises scheduler.wait and scheduler.yield are lowered
net.SocketAddress and net.BlockList were refused at compile time. They
are now native checked-dynamic handles in scr_net.c, so their getters
and methods also work on untyped values, and they match Node 24:
- new SocketAddress(options) checks the options in Node's order
(ERR_INVALID_ARG_TYPE, ERR_INVALID_ARG_VALUE for the family,
ERR_SOCKET_BAD_PORT, ERR_OUT_OF_RANGE for the flow label) and throws
ERR_INVALID_ADDRESS for an address that does not parse. parse() reads
URL.parse(`http://${input}`)'s hostname and port and answers undefined
on failure; isSocketAddress(), toJSON() and util.inspect match.
- BlockList takes address, range, subnet and CIDR rules (addAddress,
addAddresses, addRange, addSubnet, addCIDR, addCIDRs), removes them
(removeAddress, removeRange, removeSubnet, removeCIDR, clear) and lists
them in Node's order: IPv4 addresses, IPv6 addresses, subnets, then
ranges, each newest first, with a repeated address kept once.
- check() compares across families through the IPv4-mapped IPv6 form,
as Node's SocketAddress::compare and is_in_network do, and answers
false for a string that does not parse in the given family.
- rules, size, toJSON(), fromJSON() (Node's rule patterns), isBlockList(),
PRIVATE_RANGES, instanceof and util.inspect match, with the validation
errors of lib/internal/blocklist.js.
Corpus 5659 and the node-types fixture net-blocklist.ts cover both
classes.
The compatibility registry lists the BlockList methods and
SocketAddress.parse as supported, and both classes as partial: their
structured clone and worker transfer forms are not modeled.
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.
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.
new MessageChannel() from node:worker_threads makes two entangled
MessagePorts. They share the handle model of parentPort: postMessage
with the existing message clone, 'message' and 'close' events,
on/once, start, close, ref, unref and hasRef. A port's 'close' reaches
the other port after its queued messages. receiveMessageOnPort(port)
answers the next queued message as { message }, or undefined.
A channel is a thread-neutral record (scr_mailbox.c): each end has its
queue and the inbox of the thread that owns its port. A port listed in a
transfer list, given as postMessage's array or { transfer }, or as the
Worker constructor's transferList, travels with the message, and the
decoding thread adopts it. The sending port becomes unusable. A port in a
message without that listing throws DataCloneError, and so does a port
listing itself.
Port events follow Node's loop phases. Each port's queued messages
arrive as one batch, ports in creation order, before setImmediate
callbacks, with nextTicks and microtasks after each message (a new loop
hook keeps the pass going until the batch is delivered). A port's own
'close' runs in the following close phase, the latest close() first. The
other port's 'close' arrives on a later poll, in the order the notices
were sent, and only while the loop keeps running.
Buffer.from of strings, arrays and Uint8Arrays, Buffer.allocUnsafe and
Buffer.concat now return views into a per-thread pool slab of
Buffer.poolSize bytes (64 KiB by default) when the size is below
Buffer.poolSize >>> 1, following Node's allocate, fromStringFast and
fromArrayLike: 8-byte aligned offsets, a new slab when a request does not
fit, and the four-bytes-per-unit reservation for strings. Buffer.poolSize
can be read and set, and Buffer.allocUnsafeSlow returns an unpooled Buffer.
A slab lives while any of its views does. Its ArrayBuffer cannot be
transferred, and structuredClone of a typed array view copies the whole
ArrayBuffer and keeps the view's offset. Buffer.alloc, allocUnsafe and
allocUnsafeSlow validate sizes with Node's ERR_OUT_OF_RANGE error.
The first pooled allocation finds the startup slab, which has the
default 64 KiB size. A request it cannot hold gets a slab of the current
Buffer.poolSize, as in Node, and the room is checked after every new
slab, so a Buffer.poolSize raised before the first pooled allocation
cannot place a reservation past the end of a 64 KiB slab. A reservation
larger than a fresh slab traps instead of writing past it.
Corpus 5531 (typed) and 5532 (untyped) raise Buffer.poolSize before the
first pooled allocation and allocate just under the new threshold
through each pooled path, each case in a fresh child process, and also
shrink Buffer.poolSize and change it between allocations. The
node-types fenced fixture no longer lists Buffer.poolSize, which now
compiles.
node:test's mock.fn(original[, implementation]) and t.mock.fn compile.
A Mock<F> is the function-with-properties record { %call, mock }: the
callable is a wrapper closure that shares the mock context with the mock
field. The context records each call's arguments, result, error and this,
and keeps the current implementation, the original and the one-time
implementations by call index. fn.mock supports, as in Node 24.22:
- calls, read as a copy of the log;
- callCount();
- mockImplementation(fn);
- mockImplementationOnce(fn[, onCall]), for the next call by default, a
later registration for the same index replacing the earlier one;
- resetCalls();
- restore(), which brings back the original.
A throwing implementation records the error and rethrows it. Functions
with fixed parameters or a single rest array parameter are supported; a
union return type needs an undefined arm. mock.fn() without an original,
mock.method, the tracker's reset and restoreAll, and t.mock.method are
refused with SC2020.
The node:test fixture mock-fn compares the behavior with Node, and
tests/diagnostics/mock-fences.ts covers the refusals.
fs.createReadStream, fs.createWriteStream and FileHandle
createReadStream, createWriteStream and readLines return runtime
Readable and Writable streams (scr_fs_stream.c), as do new fs.ReadStream
and new fs.WriteStream in JavaScript sources. They follow
lib/internal/fs/streams.js on the stream engine:
- _construct opens the file, then emits 'open' (with the fd) and
'ready'; _read reads up to end; _write retries short writes as
writeAll does; _destroy waits for I/O in flight, then closes (with
fsync first for the flush option). Every open, read, write, fsync and
close runs on the shared worker pool.
- Options are checked in Node's order: getOptions, options.fd or the
path, start, end, then highWaterMark, encoding, emitClose and
autoClose. flags and mode are checked when the file opens, so their
errors arrive as 'error' events.
- bytesRead, bytesWritten, pending, path and close(cb) compile, also
through untyped values (close() there).
A FileHandle stream holds a reference on the handle; closing the stream
releases it and closes the handle unless autoClose is false.
FileHandle.close() follows Node's reference count: it waits for the
streams over the handle and runs their close(). readLines is a readline
Interface over createReadStream with crlfDelay: Infinity.
The stream engine gains Node's _construct (reads, buffered writes,
finish and _destroy wait for construction; destroy errors combine with
aggregateTwoErrors) and _writev, both internal. Writable.destroy() now
runs the buffered write callbacks and end() callbacks (errorBuffer),
which it dropped before. highWaterMark in a dynamic options record is
checked as getHighWaterMark does, and for await over a constructing
stream waits for construction.
Numeric flags, the fs, signal and windowsHandle options, non-UTF-8
write encodings, option functions that replace the file implementation,
and instanceof fs.ReadStream/WriteStream are refused.
Corpus 5546, 5547 and 5554 cover both lanes against Node 24.22.
node:test changes, matching Node 24.22:
- t.before, t.after, t.beforeEach and t.afterEach lower. t.before runs
when it is called; a throw fails the test and the subtests that follow,
which skip their body and beforeEach hooks and run their afterEach hooks.
t.beforeEach and t.afterEach wrap every descendant subtest. t.after runs
after the test's afterEach chain, also when the body throws, and a throw
fails the test.
- t.plan(count) counts the test's t.assert calls and subtests. A mismatch
fails the test with Node's "plan expected N assertions but received M"
string, unless an assertion failed first.
- t.fullName joins the names from the outermost suite or test with " > ".
- Tests and suites under a todo suite or test are todo, with a bare TODO
directive, unless they are skipped or carry their own todo message. A
todo suite reports its directive.
- describe.only, suite.only and { only: true } on a suite mark it. At each
level, when a child is marked or contains a marked test or suite, only
those children run.
- The failing-tests section lists failures in completion order, so
subtests come before the test that ran them, and prints thrown strings
quoted, as Node inspects them.
The fixtures ctx-hooks, ctx-plan, todo-suites, suite-variants,
only-nested and thrown-values compare the reporter output and exit code
with Node.
createInterface accepts history, historySize, removeHistoryDuplicates,
completer, tabSize and escapeCodeTimeout, as Node does for a non-terminal
interface: tabSize, escapeCodeTimeout and historySize are checked in the
constructor's order before the interface opens (ERR_OUT_OF_RANGE and
ERR_INVALID_ARG_VALUE with Node's messages), a completer that is not a
function throws ERR_INVALID_ARG_VALUE, and the values are kept on the
interface. Options may be written as shorthand properties.
rl.history answers the history option itself, or the interface's own
empty array, and historySize, historyIndex, crlfDelay, tabSize,
escapeCodeTimeout, line and terminal read as in Node. 'history'
listeners can be registered; without terminal mode Node records no
history, so they never fire.
