Converting JSON to Value with Data.Aeson

Question

How can I convert JSON to Value or Data(Haskell) with Data.Aeson or get AST with arbitrary JSON if I don't know beforehand the structure of JSON?

Answer 1

The decode function does this.

decode :: FromJSON a => ByteString -> Maybe a

Here are some examples, taken directly from the Data.Aeson module documentation:

>>> decode "{\"foo\": 123}" :: Maybe Value
Just (Object (fromList [("foo",Number 123)]))

>>> decode "{\"foo\": [\"abc\",\"def\"]}" :: Maybe Value
Just (Object (fromList [("foo",Array (fromList [String "abc",String "def"]))]))