Sequential Promise.all() in batches

batchedSequentialPromiseAll.js

const waait = i => new Promise(res => setTimeout(() => { return res(i); }, 2000));

const batchedPromiseAll = async (array) => {
    let requests = array.slice(0);

    let results = [];

    let processBatch = async (chunks, results) => {
        let curr;
        try {
            curr = await Promise.all(chunks.map(prop => waait(prop)));
            results.push(curr);
            console.log(curr);
        } catch (err) {
            throw err
        }

        return curr !== undefined && requests.length
            ? processBatch(requests.splice(0, 5), results)
            : results
    }

    const res = await processBatch(requests.splice(0, 5), results)
    console.log(JSON.stringify(res, null, 2));
}

const app = async () => {
    const array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14];
    await batchedPromiseAll(array);
}

app();