src: replace all undefined with typeMismatch

1 files changed, 5 insertions, 2 deletions

diff --git a/src/Data/ByteString/Char8/Extended.hs b/src/Data/ByteString/Char8/Extended.hs
index ca0c44a..8bf76c7 100644
--- a/src/Data/ByteString/Char8/Extended.hs
+++ b/src/Data/ByteString/Char8/Extended.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE LambdaCase #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 module Data.ByteString.Char8.Extended
     ( module Data.ByteString.Char8
@@ -5,14 +6,16 @@ module Data.ByteString.Char8.Extended
     ) where
 
 import Data.Aeson
+import Data.Aeson.Types (typeMismatch)
 import Data.ByteString.Char8
 import Data.Text.Encoding (encodeUtf8)
 import Prelude hiding (show)
 import qualified Prelude
 
 instance FromJSON ByteString where
-  parseJSON (String t) = pure (encodeUtf8 t)
-  parseJSON _ = pure undefined
+  parseJSON = \case
+      String t -> pure (encodeUtf8 t)
+      invalid -> typeMismatch "ByteString" invalid
 
 instance FromJSONKey ByteString where
   fromJSONKey = FromJSONKeyText encodeUtf8