Now, to round it back to your question: the class...

# arrow

[pakoito]

Now, to round it back to your question:

the class Json can’t map internal values from A -> B, so you can’t implement the interface Functor for it. You can try, but the types most probably won’t “align”.

If you just want the simplest possible wrapper, one that’s not like Option or List, it’s just a dumb box, we have Id. So, Id(deserialize()).map(::serialize).value works pretty much the same as deserialize().let(::serialize). The difference that Id has the interface hierarchy defined up to Monad, at the cost of the memory used by the Id wrapper and the stupid packing and unpacking to use it.