I should not need to explain to you that the problem is when b itself is internally an (m b’). Or when it is a sum of many types, of varying m-nests. I can ass

I should not need to explain to you that the problem is when b itself is internally an (m b’). Or when it is a sum of many types, of varying m-nests. I can assure you that JS libraries work with Promises just fine.