batch creation

const batchOfWhatUWant = (items, batchLength = 5000) => {
    const allItems = items
    const batchCount = allItems.length / batchLength

    return Array(Math.ceil(batchCount))
        .fill(0)
        .map((element, index) => index * batchLength)
        .map(start => allItems.slice(start, start + batchLength))
}