For .NET developers

JavaScript splits cancellation the same way .NET does: a controller that cancels (CancellationTokenSource) and a signal that observes (CancellationToken). This library fills in the members the platform lacks.

.NET	JavaScript / this library
new CancellationTokenSource()	new EnhancedAbortController()
cts.Token	controller.signal (a real AbortSignal)
cts.Cancel()	controller.abort(reason?)
cts.CancelAfter(TimeSpan)	controller.abortAfter(TimeSpan), resettable the same way
new CancellationTokenSource(TimeSpan)	EnhancedAbortController.timeout(delay)
cts.IsCancellationRequested	controller.isAborted
cts.Dispose() / using var cts	controller.dispose() / using controller (doesn’t cancel, same as .NET)
CancellationTokenSource.CreateLinkedTokenSource(a, b)	EnhancedAbortController.createLinkedController(a, b)
token.IsCancellationRequested	signal.aborted
token.ThrowIfCancellationRequested()	signal.throwIfAborted() (throws signal.reason)
token.Register(callback)	register(signal, (reason) => ...) or controller.signal.register(...)
CancellationTokenRegistration.Dispose()	registration.unregister() / using registration
token.CanBeCanceled	EnhancedAbortSignal.canBeAborted(signal)
CancellationToken.None	EnhancedAbortSignal.none
new CancellationToken(true)	EnhancedAbortSignal.aborted
Task.Delay(Timeout.Infinite, token) (wait for cancel)	await whenAborted(signal)
OperationCanceledException	isAbortError(error)
TaskCanceledException from HttpClient.Timeout	isTimeoutError(error) (a TimeoutError reason)
TimeSpan.FromSeconds(30)	TimeSpan.fromSeconds(30)
Timeout.InfiniteTimeSpan	TimeSpan.infinite (or Infinity, -1)

Differences worth knowing

• Reasons. A JavaScript abort carries a reason (any value); APIs reject with it. .NET has no equivalent: you always get OperationCanceledException. Timeouts here use a TimeoutError reason, so you can tell them from cancels without checking which source fired.
• Optional parameters. .NET passes CancellationToken token = default. In JavaScript, take signal?: AbortSignal (or default to EnhancedAbortSignal.none); createLinkedController and EnhancedAbortSignal.any skip undefined.
• Callbacks after cancellation. .NET’s Register on an already-cancelled token runs the callback synchronously; so does register here. Plain addEventListener would not.
• Timers and process lifetime. A pending CancelAfter doesn’t keep a .NET process alive either; here, in Node, the timer is unref’d for the same effect. A script that only awaits the abort exits early; see abortAfter & timeouts.
• Exceptions in callbacks. .NET aggregates them into the Cancel() call. Here a callback registered before the abort runs as an event listener; its exception is uncaught in Node. Catch inside callbacks.