derive json automatically for the way i usually write my record product types

aesont.hs

data Settings = Settings
  { settingsFoo :: Int
  , settingsBar :: String
  , settingsBaz :: [Int]
  }
  deriving (stock) Generic

instance FromJSON Settings where
  parseJSON = parseJSONFielded

instance ToJSON Settings where
  toJSON = toJSONFielded

parseJSONFielded' :: forall a.
  ( Generic a, GFromJSON Zero (Rep a))
  => Int
  -> (Value -> Parser a)
parseJSONFielded' x = genericParseJSON defaultOptions
  { fieldLabelModifier = camelTo2 '_' . drop x }
  
parseJSONFielded :: forall a.
  ( Generic a, Typeable a, GFromJSON Zero (Rep a))
  => (Value -> Parser a)
parseJSONFielded = parseJSONFielded' (tyConNameLength (Proxy @a))

toJSONFielded' :: forall a.
  ( Generic a, GFromJSON Zero (Rep a) )
  => Int
  -> (a -> Value)
toJSONFielded' x = genericToJSON defaultOptions
  { fieldLabelModifier = camelTo2 '_' . drop x }

toJSONFielded :: forall a.
  ( Generic a, Typeable a, GToJSON Zero (Rep a) )
  => (a -> Value)
toJSONFielded = toJSONFielded' (tyConNameLength (Proxy @a))

tyConNameLength :: Typeable a => Proxy a -> Int
tyConNameLength p = List.length
  . Typeable.tyConName
  . Typeable.typeRepTyCon
  $ Typeable.typeRep p