encToJsonNoSpaces
  :: ( Monoid t
     , Applicative f
     )
  => AReview Json (b, t)
  -> (a -> b)
  -> Encoder f a
encToJsonNoSpaces c f =
  encodeA (pure . review c . (, mempty) . f)

bytestring :: Applicative f => Encoder f ByteString
bytestring = encToJsonNoSpaces _JStr (_JStringBS #)

_JStringBS :: (Profunctor p, Applicative f)
             => p ByteString (f ByteString)
             -> p JString (f JString)
_JStringBS = iso (C.pack . review _JString)
                 (JString' . V.fromList . fmap utf8CharToJChar . C.unpack)