Fix #26 Validation Error Response

[sinclairzx81]

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

This PR updates the TypeBoxValidatorCompiler to return values of FastifySchemaValidationError on validation fail. This to prevent Fastify from crashing due to throwing an exception within the compiler validate callback. As of this PR, invalid data passed to the route will now result in a correct 400: Bad Request and an appropriate error object is returned on the response with a message hinting at what data is incorrect.

Note

I note that Fastify currently doesn't appear to directly export the FastifyValidationResult and FastifySchemaValidationError types. These types are accessible by importing fastify/types/schema however. I have left a comment here to potentially update the implementation with a TS assertion on the error result (for correctness), however the current error result seems to generate adequate errors with the properties specified.

Submitting for community review

[mcollina]

lgtm

I think we should return those types from Fastify

[sinclairzx81]

@mcollina Hi, is it possible to have this PR merged through or are there some upstream considerations around potentially exporting the FastifyValidationResult and FastifySchemaValidationError types first? Would be happy to update this PR to include the commented type assertion mentioned in the PR description if the latter is the case.

[mcollina]

nothing, this could land and ship. Exporting the other things would be a bonus.

I'm on vacation until Monday and I'm falling behind on releases.

[mcollina]

lgtm

[mcollina]

Can you rebase? There is a conflict.

[sinclairzx81]

@mcollina upstream changes have been merged.