dispose & lifetimes

controller.dispose() releases what the controller holds:

the pending abortAfter timer, and
the listeners a linked controller put on its parents.

It does not abort. Like .NET’s CancellationTokenSource.Dispose, it is about resources, not about stopping work. Code waiting on the signal is not woken up.

const 
const controller: EnhancedAbortController
controller = new 
new EnhancedAbortController(): EnhancedAbortController
An AbortController with .NET CancellationTokenSource features. It is an AbortController,
and controller.signal is a real AbortSignal: pass it to fetch, AbortSignal.any, streams,
timers and any other API that takes a signal.
@example 
const controller = new EnhancedAbortController().abortAfter(TimeSpan.fromSeconds(5));
const response = await fetch(url, { signal: controller.signal });
EnhancedAbortController().
EnhancedAbortController.abortAfter(delay: Delay): EnhancedAbortController
Aborts after delay, like .NET's CancelAfter: calling it again replaces the previous schedule,
and Infinity / -1 / TimeSpan.infinite cancel it. The reason is a DOMException named
TimeoutError, as with AbortSignal.timeout. The timer never keeps the process alive, and delays
longer than 24.8 days work. Does nothing once aborted. Returns the controller, for chaining.
@throws ― RangeError for NaN, negative (other than -1) or non-numeric delays.
@throws ― Error if the controller was disposed.
abortAfter(100);
const controller: EnhancedAbortController
controller.
EnhancedAbortController.dispose(): void
Releases what the controller holds: the scheduled abort and the listeners it put on linked parent
signals. It does not abort (like .NET's Dispose); call abort() first if work should stop.
abort() still works afterwards. Safe to call more than once; supports using.
dispose();

const controller: EnhancedAbortController
controller.
EnhancedAbortController.signal: EnhancedSignal
The controller's signal: a real AbortSignal, always the same object.
signal.
AbortSignal.aborted: boolean
The aborted read-only property returns a value that indicates whether the asynchronous operations the signal is communicating with are aborted (true) or not (false).
MDN Reference
aborted; // false, and the 100 ms deadline will never fire
const controller: EnhancedAbortController
controller.
EnhancedAbortController.isDisposed: boolean
True after
dispose
.
isDisposed; // true

const controller: EnhancedAbortController
controller.
AbortController.abort(reason?: any): void
The abort() method of the AbortController interface aborts an asynchronous operation before it has completed.
MDN Reference
abort('late'); // still works after dispose
// controller.abortAfter(10); // throws: a disposed controller can't schedule

After `dispose()`
`abort(reason)`	Works.
`abortAfter(delay)`	Throws `Error` (a `RangeError` first if the delay is invalid).
`dispose()` again	No-op.
Signal listeners, `register` callbacks	Untouched: they still run if you `abort()` later.

using

EnhancedAbortController implements Disposable, so using disposes it at the end of the block, however the block exits:

async function 
function withDeadline(): Promise<string>
withDeadline() {
  using 
using controller: EnhancedAbortController
controller = new 
new EnhancedAbortController(): EnhancedAbortController
An AbortController with .NET CancellationTokenSource features. It is an AbortController,
and controller.signal is a real AbortSignal: pass it to fetch, AbortSignal.any, streams,
timers and any other API that takes a signal.
@example 
const controller = new EnhancedAbortController().abortAfter(TimeSpan.fromSeconds(5));
const response = await fetch(url, { signal: controller.signal });
EnhancedAbortController().
EnhancedAbortController.abortAfter(delay: Delay): EnhancedAbortController
Aborts after delay, like .NET's CancelAfter: calling it again replaces the previous schedule,
and Infinity / -1 / TimeSpan.infinite cancel it. The reason is a DOMException named
TimeoutError, as with AbortSignal.timeout. The timer never keeps the process alive, and delays
longer than 24.8 days work. Does nothing once aborted. Returns the controller, for chaining.
@throws ― RangeError for NaN, negative (other than -1) or non-numeric delays.
@throws ― Error if the controller was disposed.
abortAfter(
class TimeSpan
An immutable time interval, stored in milliseconds. Modeled on .NET's TimeSpan.
@example 
controller.abortAfter(TimeSpan.fromSeconds(30));
TimeSpan.fromMinutes(1).add(TimeSpan.fromSeconds(30)).totalSeconds; // 90
TimeSpan.
TimeSpan.fromSeconds(seconds: number): TimeSpan
fromSeconds(5));
  return await 
function work(signal: AbortSignal): Promise<string>
work(
using controller: EnhancedAbortController
controller.
EnhancedAbortController.signal: EnhancedSignal
The controller's signal: a real AbortSignal, always the same object.
signal);
} // finished in 1 s? The 5 s timer is cleared here.

Keep the await in return await: without it the function returns the pending promise, using disposes at once, and the deadline is gone while the work still runs.

Without using:

const 
const controller: EnhancedAbortController
controller = new 
new EnhancedAbortController(): EnhancedAbortController
An AbortController with .NET CancellationTokenSource features. It is an AbortController,
and controller.signal is a real AbortSignal: pass it to fetch, AbortSignal.any, streams,
timers and any other API that takes a signal.
@example 
const controller = new EnhancedAbortController().abortAfter(TimeSpan.fromSeconds(5));
const response = await fetch(url, { signal: controller.signal });
EnhancedAbortController().
EnhancedAbortController.abortAfter(delay: Delay): EnhancedAbortController
Aborts after delay, like .NET's CancelAfter: calling it again replaces the previous schedule,
and Infinity / -1 / TimeSpan.infinite cancel it. The reason is a DOMException named
TimeoutError, as with AbortSignal.timeout. The timer never keeps the process alive, and delays
longer than 24.8 days work. Does nothing once aborted. Returns the controller, for chaining.
@throws ― RangeError for NaN, negative (other than -1) or non-numeric delays.
@throws ― Error if the controller was disposed.
abortAfter(5000);
try {
  await 
function work(signal: AbortSignal): Promise<string>
work(
const controller: EnhancedAbortController
controller.
EnhancedAbortController.signal: EnhancedSignal
The controller's signal: a real AbortSignal, always the same object.
signal);
} finally {
  
const controller: EnhancedAbortController
controller.
EnhancedAbortController.dispose(): void
Releases what the controller holds: the scheduled abort and the listeners it put on linked parent
signals. It does not abort (like .NET's Dispose); call abort() first if work should stop.
abort() still works afterwards. Safe to call more than once; supports using.
dispose();
}

Dispose, abort, or both?

You want	Call
Stop the work	`abort()`
The work finished; clean up	`dispose()` (or `using`)
Stop the work and clean up	`abort()`. An abort already releases the timer and the parent links; `dispose()` afterwards is harmless.

AbortRegistration lifetimes

register() returns an AbortRegistration, which is disposable the same way: unregister(), dispose() or using.