Customize whether an object gets transformed

[mcmath]

Currently, the keys of every non-primitive object are transformed recursively. In some cases, users may not want transform certain objects, such as Date objects (see issue #7). There should be a way for users to customize whether an object gets transformed based on a predicate function they may pass in. By default, objects such as Dates probably shouldn't be transformed.

[atlas-ssallay]

I opened a PR for this feature. We were seeing a similar issue with Date objects losing their type. I chose to not introduce a default value to prevent breaking changes to the library.

A good default would probably be to avoid transforming any of the global Javascript object types. However, that might be better as built-in behavior, separate from this option, in order to prevent a user from accidentally overriding it.

[sitvanit]

Hi, I've experienced the same issue, is there any news with the feature?
@atlas-ssallay

[odragora]

Would be very nice to see that feature released.
Currently the transformation breaks any file objects in formData.