Collect remaining fields for biome_deserialize

[NicholasLYang]

Hi,

I'm looking to use biome_deserialize_macros to parse a package.json file. We want to collect any extra fields for other tools in a map, so if we serialize the file back to text, we preserve those extra fields. Is that possible with the current macro? Basically I would like serde's #[flatten] but for biome.

[Conaclos]

It is currently not possible. How #[flatten] solves the issue? #[flatten] is to flatten nested structures? Have you a code example?

[NicholasLYang]

@Conaclos, do you think this is feasible? It's currently blocking our ability to adopt biome for parsing package.json files.

[Conaclos]

I think the current structure doesn't allow implementing easily flatten as serde supports it. However, we could implement a subset of the behavior of flatten by requiring that the type of the annotated field implements FromIterator<(K, V) (this is implemented by HashMap). What do you think? Would you like to contribute on this?

[Conaclos]

Side note: I am not sure what could be the type of the value if we didn't deserialize them...

[NicholasLYang]

Yeah that sounds good! I'll look into implementing it. Could the type of the value be AnyJsonValue?

Edit: Hmm probably not since we need it to be format agnostic. Perhaps we could create a biome equivalent of serde::Value?

[NicholasLYang]

First pass at PR here: #2757