cancellable.ts

export function cancellable<A>(
  p: Promise<A>,
  ok: (a: A) => void,
  err: (e: Error) => void,
  fin?: () => void
) {
  let cancelled = false;
  p.then((v) => cancelled || ok(v))
    .catch((e) => cancelled || err(e))
    .finally(() => cancelled || fin?.());
  return () => {
    cancelled = true;
  };
}