Could you explain further, please? I plan on changing it a bit internally but not on growing it past its purpose as I like it to do only one thing (and hopefully do it well)

I think page.js supports middleware if you're looking for something to emulate. Basically chainring callbacks.

Only reference I could find in https://visionmedia.github.io/page.js/ was:

    page(callback)

    This is equivalent to page('*', callback) for generic "middleware".

Which is... pointless? If you are going to call a function everywhere in front-end why don't you use an IIFE for scope or just nothing at all? Unless you wanted to put it on the <head> and make it load when the page is ready.

A callback is middleware, you can

    page('/some/path', middleware, callback);

I see, but I don't really like this extra functionality for pagex. I am not looking to copy express with middleware for front-end, just wanted some easy and straight way to load a script if we are in the correct part of the website.

Uh, then you and I have very different definitions of "express-like". When I think of express I think of middleware.

In the simple way, express accepts a path (url-like fragment) and executes a callback when it matches the url. THAT is what I meant from express-like, but from this and other comments I can see it wasn't clear at all.