This module is used when you define custom scalars codecs for your schema. See an example and steps for how to set this up in your codebase here: https://github.com/dillonkearns/elm-graphql/blob/master/examples/src/Example07CustomCodecs.elm
{ encoder : elmValue -> Json.Encode.Value
, decoder : Json.Decode.Decoder elmValue
}
A simple definition of a decoder/encoder pair.