Check for exact path match before checking routes

[taion]

Now that we've finally landed #3158 (hopefully for good), we can optimize isActive a bit.

Paths are fully canonical now except for possibly the trailing slash.

Thus, for checking indexOnly active state, we only need to verify that the paths are the same, net of leading/trailing slash normalization. This ought to be a lot faster than actually running the path match.

Additionally, this condition is also sufficient (but not necessary) for a route match in the general case.

[taion]

The main implication of this is that <IndexLink>s should be consistently quite a bit faster than normal <Link>s now, though I haven't benchmarked this at all.

[timdorr]

Since we're doing this twice, we can optimize a tiny bit by just moving this up to isActive itself.

[taion]

Good point.

[timdorr]

In fact, given the similarity with currentPathname as well, you can just do a method extraction here.

[taion]

I think it might be overkill to do that – this snippet is short/simple enough that I'm not too worried about duplicating it unnecessarily.

[timdorr]

Yeah, it's a nitpick. Do what you want :)

[taion]

PR updated. I think this can actually go out in a patch release – there should be no change in observable functionality.

[timdorr]

Agreed. Let's do a 2.2.3 with this in it.