Re-evaluating Node.js Experimental Features

[RafaelGSS]

I believe it's time to discuss our policies around experimental features in the project. Features like --experimental-network-import are challenging to assess and maintain, especially when there is no active champion or creator overseeing them.

Proposal

I propose that when the creator or champion of an experimental feature becomes inactive, we should:

1. Re-evaluate the benefits of the feature.
2. Decide whether to remove the feature entirely or delegate its maintenance to a team.

This approach will help us set clear expectations, assess and review vulnerabilities, and ensure better maintenance of our experimental features.

Recent Example

We recently dropped the --experimental-policy feature because:

• We were receiving reports about it.
• The documentation did not clearly define its boundaries and security expectations, making it difficult to assess.

Actionable Steps

To facilitate this discussion, I have written a simple script to list all experimental APIs from nodejs/node/docs/api/**. You can find it here.

Can we evaluate these experimental features either asynchronously or through a dedicated call?

File	API	Group Header	Re-Evaluated
doc/api/async_context.md	AsyncLocalStorage.bind(fn)	AsyncLocalStorage	:white_large_square:
doc/api/async_context.md	AsyncLocalStorage.snapshot()	AsyncLocalStorage	:white_large_square:
doc/api/async_context.md	asyncLocalStorage.disable()	AsyncLocalStorage	:white_large_square:
doc/api/async_context.md	asyncLocalStorage.enterWith(store)	AsyncLocalStorage	:white_large_square:
doc/api/async_context.md	asyncLocalStorage.exit(callback[, ...args])	AsyncLocalStorage	:white_large_square:
doc/api/async_hooks.md	AsyncHooks	Async hooks	:white_large_square:
doc/api/buffer.md	buffer.resolveObjectURL(id)	Buffer	:white_large_square:
doc/api/child_process.md	subprocess[Symbol.dispose]()	Child Process	:white_large_square:
doc/api/cli.md	--allow-addons	Permission Model	✅
doc/api/cli.md	--allow-child-process	Permission Model	✅
doc/api/cli.md	--allow-fs-read	Permission Model	✅
doc/api/cli.md	--allow-fs-write	Permission Model	✅
doc/api/cli.md	--allow-wasi	Permission Model	✅
doc/api/cli.md	--allow-worker	Permission Model	✅
doc/api/cli.md	--build-snapshot	Startup Snapshot	:white_large_square:
doc/api/cli.md	--build-snapshot-config	Startup Snapshot	:white_large_square:
doc/api/cli.md	-C condition, --conditions=condition	Conditional Exports	:white_large_square:
doc/api/cli.md	--cpu-prof		:white_large_square:
doc/api/cli.md	--cpu-prof-dir		:white_large_square:
doc/api/cli.md	--cpu-prof-interval		:white_large_square:
doc/api/cli.md	--cpu-prof-name		:white_large_square:
doc/api/cli.md	--disable-warning=code-or-type		:white_large_square:
doc/api/cli.md	--expose-gc		:white_large_square:
doc/api/cli.md	--env-file=config	Node Env	:white_large_square:
doc/api/cli.md	--experimental-default-type=type	Loaders	:white_large_square:
doc/api/cli.md	--experimental-detect-module	Loaders	:white_large_square:
doc/api/cli.md	--experimental-network-imports	Loaders	:white_large_square:
doc/api/cli.md	--experimental-permission	Permission Model	✅
doc/api/cli.md	--experimental-require-module	Loaders	:white_large_square:
doc/api/cli.md	--experimental-sea-config	SEA	:white_large_square:
doc/api/cli.md	--experimental-shadow-realm		:white_large_square:
doc/api/cli.md	--experimental-test-module-mocks	Test Runner	:white_large_square:
doc/api/cli.md	--experimental-test-snapshots	Test Runner	:white_large_square:
doc/api/cli.md	--frozen-intrinsics		:white_large_square:
doc/api/cli.md	--heap-prof		:white_large_square:
doc/api/cli.md	--heap-prof-dir		:white_large_square:
doc/api/cli.md	--heap-prof-interval		:white_large_square:
doc/api/cli.md	--heap-prof-name		:white_large_square:
doc/api/cli.md	--heapsnapshot-near-heap-limit=max_count		:white_large_square:
doc/api/cli.md	--import=module	Loaders	:white_large_square:
doc/api/cli.md	--jitless		:white_large_square:
doc/api/cli.md	--no-experimental-global-navigator		:white_large_square:
doc/api/cli.md	--run		✅
doc/api/cli.md	--snapshot-blob=path	Startup Snapshot	:white_large_square:
doc/api/cli.md	--test-update-snapshots		:white_large_square:
doc/api/cli.md	NODE_COMPILE_CACHE=dir		:white_large_square:
doc/api/cli.md	Source map cache		:white_large_square:
doc/api/corepack.md	Corepack	Corepack	:white_large_square:
doc/api/crypto.md	crypto.hash(algorithm, data[, outputEncoding])	Crypto	:white_large_square:
doc/api/dgram.md	socket[Symbol.asyncDispose]()		:white_large_square:
doc/api/diagnostics_channel.md	diagnostics_channel.tracingChannel(nameOrChannels)	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	channel.bindStore(store[, transform])	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	channel.unbindStore(store)	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	channel.runStores(context, fn[, thisArg[, ...args]])	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	Class: TracingChannel	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	tracingChannel.subscribe(subscribers)	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	tracingChannel.unsubscribe(subscribers)	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	tracingChannel.traceSync(fn[, context[, thisArg[, ...args]]])	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	tracingChannel.tracePromise(fn[, context[, thisArg[, ...args]]])	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	tracingChannel.traceCallback(fn, position, context, thisArg, ...args)	Diagnostics	:white_large_square:
doc/api/diagnostics_channel.md	Built-in Channels		:white_large_square:
doc/api/errors.md	ERR_INPUT_TYPE_NOT_ALLOWED		:white_large_square:
doc/api/errors.md	ERR_REQUIRE_CYCLE_MODULE		:white_large_square:
doc/api/errors.md	ERR_REQUIRE_ASYNC_MODULE		:white_large_square:
doc/api/errors.md	ERR_REQUIRE_ESM		:white_large_square:
doc/api/errors.md	ERR_UNKNOWN_FILE_EXTENSION		:white_large_square:
doc/api/errors.md	ERR_UNKNOWN_MODULE_FORMAT		:white_large_square:
doc/api/errors.md	ERR_USE_AFTER_CLOSE		:white_large_square:
doc/api/errors.md	ERR_NETWORK_IMPORT_BAD_RESPONSE		:white_large_square:
doc/api/errors.md	ERR_NETWORK_IMPORT_DISALLOWED		:white_large_square:
doc/api/esm.md	import.meta.dirname		:white_large_square:
doc/api/esm.md	import.meta.filename		:white_large_square:
doc/api/esm.md	import.meta.resolve(specifier)		:white_large_square:
doc/api/esm.md	JSON modules	ESM	:white_large_square:
doc/api/esm.md	Wasm modules	ESM	:white_large_square:
doc/api/esm.md	HTTPS and HTTP imports	ESM	:white_large_square:
doc/api/events.md	events.addAbortListener(signal, listener)	Events	:white_large_square:
doc/api/fs.md	filehandle.readableWebStream([options])	File System	:white_large_square:
doc/api/fs.md	filehandle[Symbol.asyncDispose]()	File System	:white_large_square:
doc/api/fs.md	fsPromises.glob(pattern[, options])	File System	:white_large_square:
doc/api/fs.md	fs.glob(pattern[, options], callback)	File System	:white_large_square:
doc/api/fs.md	fs.openAsBlob(path[, options])	File System	:white_large_square:
doc/api/fs.md	fs.globSync(pattern[, options])	File System	:white_large_square:
doc/api/fs.md	dirent.parentPath	File System	:white_large_square:
doc/api/globals.md	Class: ByteLengthQueuingStrategy		:white_large_square:
doc/api/globals.md	Class: CompressionStream		:white_large_square:
doc/api/globals.md	Class: CountQueuingStrategy		:white_large_square:
doc/api/globals.md	Crypto	Crypto	:white_large_square:
doc/api/globals.md	CryptoKey	Crypto	:white_large_square:
doc/api/globals.md	CustomEvent		:white_large_square:
doc/api/globals.md	Class: DecompressionStream		:white_large_square:
doc/api/globals.md	Navigator		:white_large_square:
doc/api/globals.md	Class: ReadableByteStreamController		:white_large_square:
doc/api/globals.md	Class: ReadableStream		:white_large_square:
doc/api/globals.md	Class: ReadableStreamBYOBReader		:white_large_square:
doc/api/globals.md	Class: ReadableStreamBYOBRequest		:white_large_square:
doc/api/globals.md	Class: ReadableStreamDefaultController		:white_large_square:
doc/api/globals.md	Class: ReadableStreamDefaultReader		:white_large_square:
doc/api/globals.md	SubtleCrypto		:white_large_square:
doc/api/globals.md	Class: TextDecoderStream		:white_large_square:
doc/api/globals.md	Class: TextEncoderStream		:white_large_square:
doc/api/globals.md	TransformStream	TransformStream	:white_large_square:
doc/api/globals.md	TransformStreamDefaultController	TransformStreamDefaultController	:white_large_square:
doc/api/globals.md	WebSocket	globals.md	:white_large_square:
doc/api/globals.md	WritableStream	WritableStream	:white_large_square:
doc/api/globals.md	WritableStreamDefaultController	WritableStreamDefaultController	:white_large_square:
doc/api/globals.md	WritableStreamDefaultWriter	WritableStreamDefaultWriter	:white_large_square:
doc/api/http.md	serverSymbol.asyncDispose	http.md	:white_large_square:
doc/api/http2.md	serverSymbol.asyncDispose	http2.md	:white_large_square:
doc/api/https.md	serverSymbol.asyncDispose	https.md	:white_large_square:
doc/api/inspector.md	Promises API	inspector.md	:white_large_square:
doc/api/module.md	module.register(specifier[, parentURL][, options])	module.md	:white_large_square:
doc/api/module.md	Customization Hooks	module.md	:white_large_square:
doc/api/module.md	initialize()	module.md	:white_large_square:
doc/api/module.md	resolve(specifier, context, nextResolve)	module.md	:white_large_square:
doc/api/module.md	load(url, context, nextLoad)	module.md	:white_large_square:
doc/api/module.md	Source map v3 support	module.md	:white_large_square:
doc/api/n-api.md	node_api_nogc_env	n-api.md	:white_large_square:
doc/api/n-api.md	node_api_nogc_finalize	n-api.md	:white_large_square:
doc/api/n-api.md	node_api_create_external_string_latin1	n-api.md	:white_large_square:
doc/api/n-api.md	node_api_create_external_string_utf16	n-api.md	:white_large_square:
doc/api/n-api.md	node_api_create_property_key_utf16	n-api.md	:white_large_square:
doc/api/n-api.md	node_api_post_finalizer	n-api.md	:white_large_square:
doc/api/net.md	serverSymbol.asyncDispose	net.md	:white_large_square:
doc/api/packages.md	Determining package manager	packages.md	:white_large_square:
doc/api/packages.md	"packageManager"	packages.md	:white_large_square:
doc/api/process.md	process.constrainedMemory()	process.md	:white_large_square:
doc/api/process.md	process.availableMemory()	process.md	:white_large_square:
doc/api/process.md	process.getActiveResourcesInfo()	process.md	:white_large_square:
doc/api/process.md	process.loadEnvFile(path)	process.md	:white_large_square:
doc/api/process.md	process.setSourceMapsEnabled(val)	process.md	:white_large_square:
doc/api/process.md	process.sourceMapsEnabled	process.md	:white_large_square:
doc/api/readline.md	Promises API	readline.md	:white_large_square:
doc/api/single-executable-applications.md	Single executable applications	single-executable-applications.md	:white_large_square:
doc/api/stream.md	writable.writableAborted	stream.md	:white_large_square:
doc/api/stream.md	readable.readableAborted	stream.md	:white_large_square:
doc/api/stream.md	readable.readableDidRead	stream.md	:white_large_square:
doc/api/stream.md	readableSymbol.asyncDispose	stream.md	:white_large_square:
doc/api/stream.md	readable.compose(stream[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.iterator([options])	stream.md	:white_large_square:
doc/api/stream.md	readable.map(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.filter(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.forEach(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.toArray([options])	stream.md	:white_large_square:
doc/api/stream.md	readable.some(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.find(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.every(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.flatMap(fn[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.drop(limit[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.take(limit[, options])	stream.md	:white_large_square:
doc/api/stream.md	readable.reduce(fn[, initial[, options]])	stream.md	:white_large_square:
doc/api/stream.md	stream.compose(...streams)	stream.md	:white_large_square:
doc/api/stream.md	stream.Readable.fromWeb(readableStream[, options])	stream.md	:white_large_square:
doc/api/stream.md	stream.Readable.isDisturbed(stream)	stream.md	:white_large_square:
doc/api/stream.md	stream.isErrored(stream)	stream.md	:white_large_square:
doc/api/stream.md	stream.isReadable(stream)	stream.md	:white_large_square:
doc/api/stream.md	stream.Readable.toWeb(streamReadable[, options])	stream.md	:white_large_square:
doc/api/stream.md	stream.Writable.fromWeb(writableStream[, options])	stream.md	:white_large_square:
doc/api/stream.md	stream.Writable.toWeb(streamWritable)	stream.md	:white_large_square:
doc/api/stream.md	stream.Duplex.fromWeb(pair[, options])	stream.md	:white_large_square:
doc/api/stream.md	stream.Duplex.toWeb(streamDuplex)	stream.md	:white_large_square:
doc/api/test.md	Watch mode	test.md	:white_large_square:
doc/api/test.md	Collecting code coverage	test.md	:white_large_square:
doc/api/test.md	Snapshot testing	test.md	:white_large_square:
doc/api/test.md	snapshot	test.md	:white_large_square:
doc/api/test.md	snapshot.setDefaultSnapshotSerializers(serializers)	test.md	:white_large_square:
doc/api/test.md	snapshot.setResolveSnapshotPath(fn)	test.md	:white_large_square:
doc/api/test.md	MockModuleContext	test.md	:white_large_square:
doc/api/test.md	mock.module(specifier[, options])	test.md	:white_large_square:
doc/api/test.md	MockTimers	test.md	:white_large_square:
doc/api/test.md	context.assert.snapshot(value[, options])	test.md	:white_large_square:
doc/api/test.md	context.plan(count)	test.md	:white_large_square:
doc/api/timers.md	immediateSymbol.dispose	timers.md	:white_large_square:
doc/api/timers.md	timeoutSymbol.dispose	timers.md	:white_large_square:
doc/api/timers.md	timersPromises.scheduler.wait(delay[, options])	timers.md	:white_large_square:
doc/api/timers.md	timersPromises.scheduler.yield()	timers.md	:white_large_square:
doc/api/tracing.md	Trace events	tracing.md	:white_large_square:
doc/api/url.md	URL.createObjectURL(blob)	url.md	:white_large_square:
doc/api/url.md	URL.revokeObjectURL(id)	url.md	:white_large_square:
doc/api/util.md	util.MIMEType	util.MIMEType	:white_large_square:
doc/api/util.md	util.parseEnv(content)	util.md	:white_large_square:
doc/api/util.md	util.styleText(format, text)	util.md	:white_large_square:
doc/api/util.md	util.transferableAbortController()	util.md	:white_large_square:
doc/api/util.md	util.transferableAbortSignal(signal)	util.md	:white_large_square:
doc/api/util.md	util.aborted(signal, resource)	util.md	:white_large_square:
doc/api/v8.md	v8.queryObjects(ctor[, options])	v8.md	:white_large_square:
doc/api/v8.md	v8.setHeapSnapshotNearHeapLimit(limit)	v8.md	:white_large_square:
doc/api/v8.md	Startup Snapshot API	v8.md	:white_large_square:
doc/api/vm.md	vm.Module	vm.Module	:white_large_square:
doc/api/vm.md	vm.SourceTextModule	vm.SourceTextModule	:white_large_square:
doc/api/vm.md	vm.SyntheticModule	vm.SyntheticModule	:white_large_square:
doc/api/vm.md	vm.constants.USE_MAIN_CONTEXT_DEFAULT_LOADER	vm.md	:white_large_square:
doc/api/vm.md	vm.measureMemory([options])	vm.md	:white_large_square:
doc/api/wasi.md	WebAssembly System Interface (WASI)	wasi.md	:white_large_square:
doc/api/webcrypto.md	Ed25519/Ed448/X25519/X448 key pairs	webcrypto.md	:white_large_square:
doc/api/worker_threads.md	port.hasRef()	worker_threads.md	:white_large_square:

(Feel free to edit this table)

[gireeshpunathil]

Re-evaluate the benefits of the feature. Decide whether to remove the feature entirely or delegate its maintenance to a team.

• may be, we could also assess where does the feature stand in terms of its progress towards stability, what are the gaps and what are the opportunities?
• may be, we could also assess where does the feature stand in terms of field adoption, what are the use cases and what the users think of about it?

[RafaelGSS]

Absolutely @gireeshpunathil.

[BridgeAR]

About having a call: I don't think a general call is useful in this case. The topics are driven by different groups of people e.g., crypto, test runner and AsyncLocalStorage. I think it would be good to try to get feedback by each group about the individual status of these.

[GeoffreyBooth]

I think it would be good to try to get feedback by each group about the individual status of these.

I think a separate issue with experimental features by topic/team would be good. Maybe a goal would be that for every feature we're leaving as experimental, we both define its stage and create a tracking issue with a to-do list of what's left before it can go stable. We've had tracking issues for several recent experimental features and I've found them useful, and they're good for communicating to users what to expect.

[ronag]

• AsyncHooks: Is there any point in still having this as experimental? IMHO it's not like it's going to be removed. In practice we are treating it as stable. It should either be doc deprecated or stable. Keeping it experimental is confusing.
• All symbol.dispose should IMO stay experimental until it's more mainstream in javascript in general.
• All web streams should IMO stay experimental until we have an active maintainer.

As I've mentioned many times before we have a more general problem with experimental features in terms of that we officially say that experimental features may change or be removed while in practice we don't want to do that due to breaking the ecosystem.

[mcollina]

I propose:

1. mark async_hooks stable.
2. keep dispose experimental until it's settled in the spec (this is true for all other spec'd things, I think we can make it a rule)
3. mark Web Streams as stable. There are enough people chipping in that I think it's time. Also it's very weird they are not becuase they are the basis for fetch().

[ronag]

1. mark async_hooks stable.

I agree with this. However, are we good with that they don't work properly with esm? Or do they?

[mcollina]

However, are we good with that they don't work properly with esm? Or do they?

I have a good feeling that they work better now that most of the loader is sync. We should do another test for that.

[RafaelGSS]

What if we start top-to-bottom?

• @Qard, what are your thoughts on AsyncLocalStorage (cc: @nodejs/diagnostics

For AsyncHooks we have the following mention on the docs:

Stability: 1 - Experimental. Please migrate away from this API, if you can. We do not recommend using the createHook, AsyncHook, and executionAsyncResource APIs as they have usability issues, safety risks, and performance implications. Async context tracking use cases are better served by the stable AsyncLocalStorage API. If you have a use case for createHook, AsyncHook, or executionAsyncResource beyond the context tracking need solved by AsyncLocalStorage or diagnostics data currently provided by Diagnostics Channel, please open an issue at https://github.com/nodejs/node/issues describing your use case so we can create a more purpose-focused API.

Having API with such a message, is that ok to move to stable? It seems Experimental will always be the place for it until we migrate things away from async_hooks.

[RafaelGSS]

Also, I'll go ahead and mark all flags related to the Permission Model as "Re-Evaluated ✅" and keep its status as experimental as we are still developing and getting more feedback along the way.

[GeoffreyBooth]

This thread is going to become unmanageable if we discuss specific APIs here. Can we get a new issue for async hooks?

[Qard]

I would doc-deprecate async_hooks and focus on the migration away from it for AsyncLocalStorage. While it is largely API stable, it's most certainly not stable from the perspective of being a thing you can trust to not crash your app. It's simply not a safe API and its use should not be encouraged.

I had asked previously for use cases not solved by ALS so we could build out some more purpose-focused APIs. There's also probably a use for a resource-tracking API which is reduced to only doing that without conflating it with promises and non-consumable resource types like http parser.

I would strongly suggest not stabilizing async_hooks in the state it is in presently. 😬

[anonrig]

--run can stay the same. just quite recently, I bumped it to release candidate. in a couple of releases, I plan to make it stable.

[joyeecheung]

Maybe we should create a new repo for this? And we PR the evaluation as documents that can be easily looked up by posterity?

(or reuse next-10 repo?)

[GeoffreyBooth]

Maybe we should create a new repo for this? And we PR the evaluation as documents that can be easily looked up by posterity?

This is a great idea. The evaluation could also include the todo list for what work remains before a feature can become stable.

[RafaelGSS]

@nodejs/next-10 can we transfer it to Next-10 and start creating issues to debate each topic? It should be async, no need to add to the agenda.

[marco-ippolito]

@nodejs/next-10 can we transfer it to Next-10 and start creating issues to debate each topic? It should be async, no need to add to the agenda.

SGTM