case res of
        Right (Right out) -> do
          verbosePut config $ "Compiled " ++ hsRelativePath f
          writeFile (jsPath config f) out
          return $ Success out
        Right (Left err) -> do
          let errString = "snaplet-fay: Error compiling " ++ hsRelativePath f ++ ":\n" ++ show err
         -- putStrLn $ C.unpack (A.encode (C.pack $ escape errString))
          putStrLn $ escape errString
          -- return Success so the browser will treat this as a normal JavaScript file.
          -- As of writing this, this means that Error is not used.
          return $ Success $ "console.error('" ++ (C.unpack . A.encode) (escape errString) ++ "');"
        Left err -> do
          let errString = "snaplet-fay: Error compiling " ++ hsRelativePath f ++ ":\n" ++ show err
          putStrLn $ escape errString
          -- return Success so the browser will treat this as a normal JavaScript file.
          -- As of writing this, this means that Error is not used.
          return $ Success $ "console.error('" ++ (C.unpack . A.encode) (escape $ errString) ++ "');"
        where
          escape s = T.unpack $ T.replace (T.pack "'") (T.pack "\'") (T.pack s)