@@ -33,6 +33,7 @@ module Data.Aeson.Types.Class
3333 , fromJSON
3434 , (.:)
3535 , (.:?)
36+ , (.:/)
3637 , (.=)
3738 , typeMismatch
3839 ) where
@@ -707,6 +708,20 @@ obj .:? key = case M.lookup key obj of
707708 Just v -> parseJSON v
708709{-# INLINE (.:?) #-}
709710
711+-- | Retrieve the value associated with the given key of an 'Object'.
712+-- The result is a default value if the key is not present, or 'empty'
713+-- if the value cannot be converted to the desired type.
714+--
715+-- This accessor is most useful if the key and value can be absent
716+-- from an object without affecting its validity and we know a
717+-- default value to assign in that case. If the key and value
718+-- are mandatory, use '(.:)' instead.
719+(.:/) :: (FromJSON a) => Object -> (Text, a) -> Parser a
720+obj .:/ (key, val) = case M.lookup key obj of
721+ Nothing -> pure val
722+ Just v -> parseJSON v
723+{-# INLINE (.:/) #-}
724+
710725
711726-- | Fail parsing due to a type mismatch, with a descriptive message.
712727typeMismatch :: String -- ^ The name of the type you are trying to parse.