Thank you for working on this @productdevbook and thanks for the suggestions @OskarLebuda ❤️

I have pushed some refactors (mostly temporary code removals) to make the PR small enough to merge and iterate.

A summary of changes:

• No duplicate method and route added to custom route meta (h3 already keeps this info in H3Route.{method,route}
• Removed extra response and params validation from defineRoute (both really good ideas!!), instead of duplicating a logic that can diverge from defineValidatedHandler capabilities, we should add them to defineValidatedHandler
• Used flatten options (validate: { query, ... }) to be consistent with current defineValidatedHandler
• Removed extensive example, the biggest benefit of defineRoute is it's modularity that encapsulates all route definition. Validation, Type safety and Middleware while also possible with this util, they are generic h3 features via define* utils.

Next steps: (if you like to contribute please split PRs, it makes it much faster to iterate 🙏🏼)

• Improve defineValidatedHandler utility: (all will be also supported to defineRoute)
  • Auto assign .meta from definition (fix: fix(defineValidatedHandler): accept all EventHandlerObject props #1147)
  • Use { validate: { query, ... } } syntax for more clarity (refactor!(defineValidatedHandler, defineRoute): use validate: {} namespace #1148)
  • Support response and route param validation
  • Probably also a good time to document it in the data validation section (/cc @sandros94)
• Improve defineRoute (internal) type safety by augmenting H3Event generics from validate functions
• It would be nice if you could make a stackblitz demo for "Books App" using H3 and defineRoute we could link it as an interactive example to the docs once tested enough