Use builtin camelTo2 function

tea-cleaner/TeaCleaner/Options.hs

@@ -6,23 +6,9 @@ module TeaCleaner.Options
     ( jsonOptions
     ) where
 
-import qualified Data.Aeson.TH as Aeson
-import Prelude hiding (id)
-import Data.Char
-
-applyFirst :: (Char -> Char) -> String -> String
-applyFirst _ []     = []
-applyFirst f [x]    = [f x]
-applyFirst f (x:xs) = f x: xs
-
--- | Generic casing for symbol separated names
-symbCase :: String -> String
-symbCase = u . applyFirst toLower
-  where u []                       = []
-        u (x:xs) | isUpper x = '_' : toLower x : u xs
-                 | otherwise = x : u xs
+import qualified Data.Aeson as Aeson
 
 jsonOptions :: Aeson.Options
 jsonOptions = Aeson.defaultOptions
-    { Aeson.fieldLabelModifier = symbCase
+    { Aeson.fieldLabelModifier = Aeson.camelTo2 '_'
     }