dunkirk.sh
pstream is dead; long live pstream
taciturnaxolotl.github.io/pstream-ng/
1/**
2 * Maps an array to a promise that resolves with an array of results,
3 * limiting the number of concurrent operations.
4 *
5 * @param items The array of items to map
6 * @param concurrency The maximum number of concurrent operations
7 * @param fn The async function to apply to each item
8 * @returns A promise that resolves with an array of results
9 */
10export async function concurrentMap<T, R>(
11 items: T[],
12 concurrency: number,
13 fn: (item: T) => Promise<R>,
14): Promise<R[]> {
15 const results: R[] = new Array(items.length);
16 const queue = items.map((item, index) => ({ item, index }));
17
18 const workers = Array.from(
19 { length: Math.min(concurrency, items.length) },
20 async () => {
21 while (queue.length > 0) {
22 const entry = queue.shift();
23 if (!entry) break;
24 const { item, index } = entry;
25 results[index] = await fn(item);
26 }
27 },
28 );
29
30 await Promise.all(workers);
31 return results;
32}