návrat dátum čas objekt v rrrr-mm-dd h:min:sek
const str = (new Date()).toISOString().slice(0, 19).replace(/-/g, "/").replace("T", " ");
python datetime formáte rrrr-mm-dd
from datetime import datetime
now = datetime.today().isoformat()
print(now) # '2018-12-05T11:15:55.126382'