Support AbortController

[kripod]

Thank you for this awesome solution for debouncing Promises!

How should this library be used together with p-cancelable?

[sindresorhus]

Browsers and Node.js now support AbortController, so maybe we could support that somehow.

[kripod]

Sounds great if native support for that could be added! 🙌

Until then, do you have any idea about how to debounce Promises with cancelation functionality?

I would like to create debouncers with multiple intervals (e.g. 1000ms, 400ms, 0ms) for the same Promise. Once any of them is called (e.g. the one with 400ms debouncing), all the other debouncers are canceled.

[kripod]

After long hours of trying, I coudln’t find a way to make pDebounce()-ed callbacks cancelable from the outside. @sindresorhus I would appreciate your help guiding through this process.

[kripod]

I just came up with a barebones solution by combining this library’s code with p-cancelable’s:

export type Cancelable = {
	cancel: (reason?: unknown) => void;
};

export class CancelError extends Error {
	constructor(reason?: string) {
		super(reason || "Promise was canceled");
		this.name = "CancelError";
	}
}

export function debouncePromise<T, P extends unknown[]>(
	callback: (...args: P) => T,
	msDelay: number,
) {
	let timeoutId = 0;
	let resolves: Array<(value: T | PromiseLike<T>) => void> = [];
	let rejects: Array<(reason?: unknown) => void> = [];

	function reset() {
		timeoutId = 0;
		resolves = [];
		rejects = [];
	}

	function cancelableCallback(...args: P) {
		return new Promise<T>((currentResolve, currentReject) => {
			window.clearTimeout(timeoutId);
			timeoutId = window.setTimeout(() => {
				const result = callback(...args);
				resolves.forEach((resolve) => {
					resolve(result);
				});
				reset();
			}, msDelay);

			resolves.push(currentResolve);
			rejects.push(currentReject);
		});
	}

	cancelableCallback.cancel = (reason: unknown = new CancelError()) => {
		window.clearTimeout(timeoutId);
		rejects.forEach((reject) => {
			reject(reason);
		});
		reset();
	};

	return cancelableCallback;
}

I would love to see similar functionality baked into p-debounce.

[rinogo]

Being able to cancel a debounced promise would be very useful! At the moment, we're stuck with using a flag to "skip" the related functionality once the "canceled" debounced call executes. It works, but it feels messy and brittle.