js create batches from array
function splitToBulks<T>(arr: T[], bulkSize: number = 20): T[][] {
const bulks: T[][] = [];
for (let i = 0; i < Math.ceil(arr.length / bulkSize); i++) {
bulks.push(arr.slice(i * bulkSize, (i + 1) * bulkSize));
}
return bulks;
}