Order by in js sdk

How do I do this in js sdk .order function:

order by (SP.target_impressions-SP.served_impressions) desc, updated_at desc

order by (SP.target_impressions-SP.served_impressions) desc, updated_at desc

order by (SP.target_impressions-SP.served_impressions) desc, updated_at desc

order by (SP.target_impressions-SP.served_impressions) desc, updated_at desc