Allow usage of patchRoutesOnNavigation in framework mode

[Bricklou]

I use React Router 7 in framework mode (with ssr: false for spa) since I want to keep the advantages of routes config and middleware from the framework.

On the other hand, I would like to make my app structured as a micro-frontend. To do so, I use module federation, and it works well, or maybe until I need to have a router in my modules…

My problem is simple: when using framework mode, I would like to be able to call patchRoutesOnNavigation so I can have lazy discovery for my modules routes. But to do so, some modifications are needed in react-router to allow this.

On the implementation side, i was seeing something similar to what loader and action function are currently doing, but inside the routes.ts file:

// app/routes.ts
import { index } from '@react-router/dev/routes' 
import type { RouteConfig, AgnosticPatchRoutesOnNavigationFunction } from '@react-router/dev/routes'

export default [
  index('routes/index.tsx', { id: 'root' })
] satisfies RouteConfig

export const patchRoutesOnNavigation: AgnosticPatchRoutesOnNavigationFunction = async ({ path, patch }) => {
  if (path === "/a") {
    // Load/patch the `a` route as a child of the route with id `root`
    let route = await getARoute();
    //  ^ { path: 'a', Component: A }
    patch("root", [route]);
  }
}