Test Type Coverage

[Ethan-Arrowood]

I'd like to start a discussion about a feature request code / test coverage.

In Fastify type system, we have a collection of type definition files that are fairly exhaustive. While we are working hard to write tests for everything, right now we cannot be certain we are covering everything.

If we could add coverage reporting to this library that would be fantastic! Do the library authors have any ideas on how this could be implemented? I've never worked with testing tooling before so I wouldn't know where to start in adding this feature. Maybe others have some valuable input.

[sindresorhus]

Some prior art:

• https://github.com/plantain-00/type-coverage
• https://github.com/codechecks/typecov
• https://github.com/jeroenouw/liftr-tscov
• https://github.com/durad/tscover

[tommy-mitchell]

See #196 for discussion on this.