feat(core): add better support for form-data arrays

[AllieJonsson]

Status

READY

Description

Fixes #1417 (appending [] to formData key name) and adds support for exploding the formData properties as well.
I need this in my current project at work, so I added it here as well.

[soartec-lab]

I'll check it later!

[anymaniax]

@AllieJonsson not related to the pull request. Could you check your discord messages when you have the time

[soartec-lab]

@AllieJonsson
I added comments 👍
could you check it ?

[soartec-lab]

This may not be necessary.
If necessary, why not consider specifying explode separately?

https://swagger.io/docs/specification/v3_0/serialization/

[soartec-lab]

And if this is removed, it can be made into a simple option like override.formData.serializeWithBrackets: true 👍

[AllieJonsson]

But that doesn't allow you to specify how body data in multipart/form-data requests are serialized, right?

[soartec-lab]

I thought that if override.formData.serializeWithBrackets was set to true, brackets would be added, and if it was set to false, it would behave as before.

[AllieJonsson]

Yes, I was thinking about the explode, how would you configure it to explode form data?
What I need for it to work with my ASP.Net backend is instead of

data.forEach(
  (value, index) => {
    formData.append(
      `receptionFacilitiesPerFaction`,
/* 
 * value is of type
 * {
 *   fractionId: number
 *   receptionFacilityIds: number[]
 * }
*/
      JSON.serialize(value),
    );
  },
);

I need to set

data.forEach(
  (value, index) => {
    formData.append(
      `receptionFacilitiesPerFaction[${index}].fractionId`,
      value.fractionId.toString(),
    );
    value.receptionFacilityIds.forEach((v, rIndex) => {
      formData.append(
        `receptionFacilitiesPerFaction[${index}].receptionFacilityIds[${rIndex}]`,
        v.toString(),
      );
    });
  },
);

[soartec-lab]

Wow, so ASP.net can't accept it unless it's in a format like receptionFacilitiesPerFaction[0]&receptionFacilitiesPerFaction[1]?

[AllieJonsson]

I was surprised as well, I couldn't get it to work with sending json objects in a multipart/form-data, so I asked ChatGPT, which gave me this solution, and it worked!
https://chatgpt.com/share/67ff8e02-1fb0-8000-901b-61e336ddad0e

[soartec-lab]

I see, I didn't know that.

[soartec-lab]

@AllieJonsson
Okey, then we already have override.formData so let's just move up the options level like override.formData.arrayHandling.

[soartec-lab]

It's good!

[soartec-lab]

@AllieJonsson
I merged #2038 so could you try rebase master?

[soartec-lab]

Thanks!