[3np]

To add on this: Looks like you can do that for directories as well. Here's how it works: https://github.com/lucacasonato/fresh/blob/4bb07f4bcebfc2056...

So the example above could be:

  user/[username]/page/[pagename].ts

[PontifexMinimus]

Hmmm. I suspect there is some software out there that doesn't like directory names with square brackets in them.