Allow providing own RouterMatcher or allow access to it from Router

[ml1nk]

What problem is this solving

The RouterMatcher which can be created by createRouterMatcher allows us to extract metadata like the params of a route which are otherwise inaccessible inside Router (RouteRecordNormalized vs RouteRecordMatcher). Currently there is no way (known to me) to provide an existing RouterMatcher to createRouter or access it inside the Router object.

Proposed solution

1. add getMatcher() in Router
2. allow RouterMatcher in RouterOptions.routes

export const routerMatcher = createRouterMatcher(routes, {})
export const router = createRouter({
  routes: routerMatcher
})

3. add RouterOptions.matcher and ignore RouterOptions.routes if set

Describe alternatives you've considered

As a workaround it is currently possible to create router and routerMatcher separately and use addRoute on both of them whenever needed. This leads to two identical RouterMatcher objects which i want to avoid.

[posva]

This is intentionally not exposed to reduce API surface and allow internal changes without breaking changes for users. I have thought of exposing some of these APIs separately but I'm not 100% sure about allowing a matcher option. An RFC to explore the use cases of this would definitely be needed before adding it. It should also define the API needed by the RouteMatcher, which you can of course copy from Vue Router source code as a starting point.

Why do you need to extract params of a route param for?

[ml1nk]

We are implementing custom role views in addition to the default technician view. To unify the navigation between the role views we are merging query and params, as it is hard to make sure the necessary params are explicit in all role view routes. In addition we allow to clear optional params as a option in our wrapper and normally carry all parameters around until explicit discarded.