Better typed fetch/$fetch

[pi0]

Context, work, and explanation by @danielroe: #1532

We are thinking of improving (auto-generated) typed fetch. This requires adopting a new standard/reusable type utility for fetch, which @danielroe is working on. By using the new layer, we can improve performance and consistency and adopt it in several places instead of directly being in nitro core (benefiting nuxt, and in the next steps ofetch and h3 typed fetch support.)

Relevant linked issues: (some might be doable in next steps)

• Type inference and code execution interrupted by undocumented SerializeObject #1138
• $fetch infered type for Date is wrong #2689
• $fetch type safety for query and body parameters #938
• Types for route inputs #841
• NitroRoute Serialize Type #2583
• Typescript shows server option doesn't exist for generic form of $fetch #1937
• TS error Excessive stack depth comparing types when trying to wrap $fetch #470

[ImBoop]

Improving fetch types would be an immense QOL improvement. I for one am very excited about this and am looking forward to more info as y'all push forward with it.

[NothingEverWorks]

Will this also type readBody to match the json serialization similiar to #1002?

And will this support alternative serializer to maintain type safety similiar to https://nuxt.com/docs/getting-started/data-fetching#using-an-alternative-serializer?

[ImBoop]

Is this still planned? To my knowledge, it's one of the things gating Nuxt 4