In Jason/Poison it is possibe to encode tuple values using defimpl Encoder, for: Tuple do def encode(data, options) when is_tuple(data) do data |> Tuple.to_list() |> Encoder.List.encode(options) end end But it seems like there is no way no encode maps with tuple keys … right? EDIT…

Thanks for the insights guys. conclusion: its not possible to hook into encoding of the keys if you really want to, do it manually or: flatten the maps, eg %{{1, 2} => %{...} becomes [%{key_: [1, 2], ...}, ...] for the task I originally had (looking at data) use inspect(data, pretty: true, limit: …

JSON only supports objects with string keys. Jason therefore only support maps whose keys are strings (or can be turned into strings using the String.Chars protocol). (I expect Poison to do the same, but I have not tested it myself.) JSON is quite a peculiar format because it is unversioned but a…

Sorry for the bad question. I want to encode the tuple to a String, so that I get valid JSON key.

What is the goal? Do you want to be able to read the resulting data from another language, or from another Elixir program? Do you need to be able to decode the key-strings back to their tuple values or not? What is contained inside the tuple elements?

[image] Sebb: I’m looking for a way to explicitly transform the tuples to a valid json key (a string). For example sth like The way that I’d do this is with an actually explicit transformation. As in, instead of map_with_tuple_keys |> Jason.encode! do map_with_tuple_keys |> keys_to_strings |> …

Actually I just wanted to have a look at my data and tried to create JSON which I’m used to. Now I discovered, that inspect(data, pretty: true, limit: infinity) Is a better way to do that, but still I’d just like to know if there is a way to explicitly encode the keys (like we can values).

I like the approach @benwilson512 shared. If you want to explicitly encode your map keys, call a function on your map to turn them into strings before calling Jason.encode! or another encoding function. You could encode those tuples using inspect(). If you want to be able to decode datatypes late…