Add static part before optional parameter?

[hackel]

I've been trying to come up with a way to have an optional parameter proceeded by an identifying static part. e.g.

{ path: '/a/:a/b?/:b?' }

What I'm after is for /a/123 and /a/123/b/456 to point to the same route, without having to duplicate the route definition. Is there any way to achieve this? Also, I would need to be able to navigate to the static part of the route with { name: 'my.route.name', params: { a: 123, b: 456 } }. I have a whole series of routes that I need to add this optional parameter to, and I don't want to have to repeat the route definition for them all. Note that /a/123/b should not be valid in this case.

Thanks!

[posva]

Adding an alias without the parameter should work