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abortable ​

Problem ​

You have a long-running promise that has no built-in cancellation support and need to race it against an AbortSignal so it rejects when the signal fires.

Solution ​

Use abortable(promise, signal) to wrap any promise and reject it when the signal aborts.

ts
import { abortable, isAbortError } from '@vielzeug/arsenal';

const controller = new AbortController();

const task = abortable(
  fetch('/api/slow').then((r) => r.json()),
  controller.signal,
);

setTimeout(() => controller.abort(), 2_000);

try {
  const data = await task;
} catch (err) {
  if (isAbortError(err)) console.log('cancelled');
  else throw err;
}

Pitfalls ​

  • The wrapped promise continues running after cancellation — abortable only rejects the returned promise, it does not stop the underlying work. Pair with fetch's signal option for true cancellation.
  • If the signal is already aborted when abortable is called, the returned promise rejects immediately.