typescript snippets

asyncBatchMap.ts

// Create batches out of big array
// Map those batches to a lambda
export async function asyncBatchMap<T, F>(
    items: ReadonlyArray<T>,
    predicate: (input: T[]) => Promise<F>,
    batchSize: number = 10,
): Promise<F[]> {
    const newContainer = items.map((e) => e);
    const result: F[] = [];
    while (newContainer.length > 0) {
        const batch = newContainer.splice(0, batchSize);
        const batchResult = await predicate(batch);
        result.push(batchResult);
    }
    return result;
}