feat: better types for params

[pcattori]

The types registered by the new generated +routes-pre.ts file are used internally to compute more precise params types for each route. Specifically, each route's params are a union of all possible params from any pages (visitable URLs) that include that route.

For example:

// routes.ts
import { type RouteConfig, route } from "@react-router/dev/routes";
          
export default [
  route("parent/:p", "routes/parent.tsx", [
    route("route/:r", "routes/route.tsx", [
      route("child1/:c1a/:c1b", "routes/child1.tsx"),
      route("child2/:c2a/:c2b", "routes/child2.tsx")
    ]),
  ]),
] satisfies RouteConfig;

Previously, we calculated the types for routes/route to be { p: string, r: string }, but this is incorrect as it ignores possible params from child routes.

Let's consider the possible params types for routes/route:

Path	Page includes routes/route?	Params type
parent/1	❌	{ p: string }
parent/1/route/2	✅	{ p: string, r: string }
parent/1/route/2/child1/3/4	✅	{ p: string, r: string, c1a: string, c1b: string }
parent/1/route/2/child2/5/6	✅	{ p: string, r: string, c2a: string, c2b: string }

So the correct params type is a union of all the params types for pages that includes routes/route:

type Params =
  | { p: string, r: string }
  | { p: string, r: string, c1a: string, c1b: string }
  | { p: string, r: string, c2a: string, c2b: string }

We could stop here, but this will lead to poor DX as autocompletion for params. will only suggest fields that exist in all members of the union. To fix this, we normalize the members of the union and add ?: undefined entries for any fields not present in the current member but present in other members:

type NormalizedParams =
  | { p: string, r: string, c1a?: undefined, c1b?: undefined, c2a?: undefined, c2b?: undefined }
  | { p: string, r: string, c1a: string, c1b: string, c2a?: undefined, c2b?: undefined }
  | { p: string, r: string, c1a?: undefined, c1b?: undefined, c2a: string, c2b: string }

This new type is equivalent to the unnormalized Params type, but allows for better DX from autocompletions.

---

This PR also reorganizes the generated files for types as:

• +future.ts : Automatic registration of future flag types
• +pages.ts : Types relevant to each visitable URL including params. Powers href types.
• +routes-pre.ts : Types derived from routes config, prior to seeing any route modules
• +routes-post.ts : Coming soon! Not part of this PR, but this will allow us to register module-aware types for routes!
• +server-build.d.ts : Types for virtual:react-router/server-build (previously +virtual.d.ts)

TODO

• unstage todo.md + playground changes
• Remove outdated typegen modules
• Fix existing typegen tests
• test for parent, route, child1, child2
• Tests for Normalize
• Changeset
• clean out old +register and +virtual from existing projects?
• fix params type for layouts

[changeset-bot]

🦋 Changeset detected

Latest commit: d152143

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@react-router/dev	Patch
react-router	Patch
@react-router/fs-routes	Patch
@react-router/remix-routes-option-adapter	Patch
@react-router/architect	Patch
@react-router/cloudflare	Patch
react-router-dom	Patch
@react-router/express	Patch
@react-router/node	Patch
@react-router/serve	Patch
create-react-router	Patch

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[github-actions]

🤖 Hello there,

We just published version 7.6.1 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!