Is it possible to parse json with mixed lists?

At first: Thanks for this library! I’m working with it to parse JSON responses from an API and it really works like a charm. If I correctly create types for the expected response, I can work type-safe with that data. But now the API sends inconsistent data, I get a list where complex objects and strings are mixed.

It looks like that: { "downloads": [ [ "English", {..} ] ] }

Is there some elegant way to handle such mixed lists with this library? I tried different approaches but none worked.

[sebastian]

Thank you @NicoVIII! I really appreciate your detailed answer and the links! A year or not, I still learnt lots reading this!

[NicoVIII]

Hi! I’m very sorry that I didn’t answer in time and am quite sure, that my answer now will not help you since it took me over a year…

I personally used Transforms to read out my information in a helpful way for me. You can have a look at that here: https://github.com/NicoVIII/GogApi.DotNet/commit/7a89344ca8da7164d7f4f0190031fd9887957c99

I’m not very experienced in F# (I only use it in hobby projects) so I’m not sure if this is the best way. But I guess a similar approach could work to get a list like you requested there:

Write a Transform from DecodedValue list into a obj list and write transformation functions for both directions (or only the one you need, I used only one direction, because I’m only reading) and add it to the field with [<JsonField(Transform=typeof<...>)>].

To transform the types I cast it one by one to the assumed type (for me the type at pos 1 was always the same). I’m not sure how to get the correct type here for the DecodedValue DU, but I guess you could use a type match approach?

// Untested - call it Pseudocode
match something with
| :? string as value -> String value
| :? int as value -> Integer value
...

(https://fsharpforfunandprofit.com/posts/match-expression/#matching-on-subtypes)

Maybe this helps when people in the future need something like that again…