Prerequisites

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🚀 Feature Proposal

Currently, the typing system of fastify is just good to use.
However, it restricted the usage on certain way and may not be good enough.
I open a new issue here for investigating how can we improve the typing system before fastify@5 lands (around 1 year later).

We have plenty idea of this area but do not have enough effort to push thing forward.
I hope community can put their effort together with us and improve this area.

1. Unify of using object Generic

We add a lot of Generic in the typings system, it is easy to use without modify the Generic.
However, when we override one of them. It will collide with the others types.
Unify of using object Generic can prevent this problem.

#3642 is the first attempt of refactoring.

2. Promote chaining fastify types

This approach is similar to Express and Koa which is optimal solution for stacking up decorated instance.
fastify/fastify-type-provider-typebox#5 (comment)

Motivation

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Example

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