doAbortable

doAbortable.ts

export default async function doAbortable<R>(
    signal: AbortSignal | undefined,
    func: (abortSignal: AbortSignal) => R | Promise<R>,
): Promise<R> {
    const controller = new AbortController();
    const abortInner = () => controller.abort();
    if (signal?.aborted) {
        abortInner();
    } else {
        signal?.addEventListener("abort", abortInner, { once: true });
    }
    try {
        return await func(controller.signal);
    } finally {
        // remove listener from the original signal, this allows our local controller
        // to be collected as there are no longer any references to it, by consequence
        // this allows the inner signal to be collectable as long as no references remain
        signal?.removeEventListener("abort", abortInner);
    }
}

example.ts

import doAbortable from "./doAbortable.ts";
import AbortError from "./AbortError.ts";

export default function delay(time: number, abortSignal?: AbortSignal): Promise<void> {
    return doAbortable(abortSignal, abortSignal => {
        return new Promise((resolve, reject) => {
            if (abortSignal.aborted) { reject(new AbortError()) }
            const timeout = setTimeout(resolve, time);
            abortSignal.addEventListener('abort', () => {
                clearTimeout(timeout);
                reject(new AbortError());
            }, { once: true });
        });
    });
}