Add support for transform types

[ehaynes99]

fixes #125

Checklist

• run npm run test and npm run benchmark (tests pass, but no benchmark script exists)
• tests and/or benchmarks are included
• documentation is changed or added (I don't think this needs an update)
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[mcollina]

Could you adjust the versions in CI?

[ehaynes99]

Could you adjust the versions in CI?

Ah, sorry, didn't know that existed.

[mcollina]

What would happen if a TransformType is used with the stock validator compiler?

[ehaynes99]

What would happen if a TransformType is used with the stock validator compiler?

Hrmm, yeah, I guess that won't work. Honestly I've just always used these together. I guess that means that this would need two independent type providers, e.g. TypeBoxTypeProvider and TypeBoxTransformTypeProvider, and require the user to pick based on whether the validator compiler is used or not.

Regarding the tests, I'll try to track down which specific version had StaticDecode. I thought it was in 0.30.0 based on the changelog, but apparently not.
https://github.com/sinclairzx81/typebox/blob/master/changelog/0.30.0.md

I'll close this for now and try to come up with something else. It'll probably be a few days before I can get back to it though.

[tothdanielax]

@ehaynes99, followed your setup as it is super handy for our scenario. But it seems the conversion works only for query, params and headers. Is there a way to decode the body also (I receive ids represented as strings and it's needed to be converted to Mongo ObjectIds)?

[ehaynes99]

@tothdanielax Hrmm, I'm not sure how that's possible. The test I added for 'should decode transform types' actually only tests the body conversion, not query or path, so if anything wasn't working, I would expect it to be one of the others.

The TypeBox author added a PR for this a while ago, but ended up closing it because of the version range issue. That's probably a better way forward because it handles the case @mcollina mentions as it precludes the combination of transform types without transforms in the validator compiler.

Sorry, I've been pretty swamped, but I'll try to resurrect that one instead.
See:
sinclairzx81/typebox#343 (comment)

I think the syntax can easily be adapted to have flags for the other two new options (though i guess that would prompt an even narrower version range, so we could add it separately).

Using the same parameter names from ajv, that could look something like:

const fastify = TypeBoxTransformProvider(Fastify(), {
  removeAdditional: true,
  useDefaults: true,
})