queue

The createQueue() function creates a FIFO queue that limits how many tasks run in parallel and exposes their results through promises.

Interactive example

Syntax

interface Queue {
	add<GenericOutput extends unknown>(
		theFunction: () => GenericOutput
	): Promise<
		| Awaited<GenericOutput>
		| DEither.Left<"execution-error", unknown>
	>;
	addExternal(): Promise<() => void>;
}

interface CreateQueueParams {
	concurrency?: number;
}

function createQueue(
	params?: CreateQueueParams
): Queue;

Parameters

• params.concurrency : Maximum number of tasks executed in parallel. Values lower than 1 fall back to 1.

Return value

A Queue object with:

• add : adds a task to the queue and returns a promise resolved with its result or with DEither.left("execution-error", error) when execution fails.
• addExternal : reserves one execution slot and returns a release function to free that slot later.

See also

• externalPromise - Creates a promise controllable from the outside
• callThen - Normalizes sync and async value handling
• asyncRetry - Retries an async operation with a retry strategy