The Future of CSS: Target Multiple Classes with the Class Prefix Selector

23 pointsposted 11 hours ago
by cdrnsf
(bram.us)

10 Comments

jjcm

10 hours ago

In their example, they list btn-* as the selector catch all for .btn-primary|secondary|danger. I can't help but think why not just do, .btn.primary for the class name, and just target .btn with the selector?

Don't get me wrong, I appreciate the convenience of this, but I do worry about selector slowdown with what will effectively turn into a regex at some point. I'm dubious that this is needed.

graypegg

10 hours ago

I have noticed it's pretty common for devs used to CSS-in-JS to imagine classes as being an exact 1:1 mapping to a specific DOM element, so maybe this is aiming to simplify things for that crowd? I guess similarly to BEM class names from a several years back.

Personally I prefer `class="btn primary"` over `class="btn-primary"` just because it aligns conceptually with what "class" literally means, but I have run into folks that would think it's confusing that there's no top-level .primary rule.

For performance... ehhhh yeah. Nesting and :has() already let you easily slow stuff down if you're not careful. Adding just wildcards, even if they're as restrictive as the blog post talks about, is still going to hang another easy-to-reach footgun on the proverbial wall.

nhinck2

9 hours ago

> Personally I prefer `class="btn primary"` over `class="btn-primary"` just because it aligns conceptually with what "class" literally means, but I have run into folks that would think it's confusing that there's no top-level .primary rule.

Especially now that there is native nesting, these prefix selectors really seem like the wrong way to go.

dymk

10 hours ago

Personally, I don't think this is a great change to CSS. I prefer being able to grep for identifiers to see where they're used. Now you can't rely on that - maybe a rule is now covered by a prefix selector.

zetanor

9 hours ago

I suppose someone could have done

  [class^="btn-"], [class*=" btn-"]
which would have equally thrown you off, but I do agree that encouraging this is unfortunate.

graypegg

9 hours ago

   *[class*=btn-] { ... }
I know you'd be matching on the class attribute instead of a single classname, but I feel like we'd see this much more out-in-the-wild if there was an apetite for this syntax feature right?

Like, the issue of `some-other-btn-primary` also matching the rule is pretty inconvenient, but definitely tolerable if people preferred writing style rules like this.

lukeify

7 hours ago

So the class prefix is actually `-*`, not `*`:

> The Class Prefix Selector is currently limited to hyphen-separated prefixes, at least at first. Other separators, like _, might be added as possibilities in the future as we receive request from authors like yourself about what would be needed.

I'm sorry, but how did they think this a good idea? Why treat the hyphen with special qualities over any other non-whitespace separator? The argument around "accidental overselection" seems pretty weak to me. If you're using a character with known special properties like the asterisk in CSS then you should understand you're wielding a more powerful hammer implicitly.

CM30

9 hours ago

This is pretty neat. Definitely seems like something that'll make writing CSS for similar classes a lot more convenient, and another example of how modern CSS seems to be adding a ton of features to make front-end development a lot more efficient.

The increased level of power HTML, CSS and JavaScript have now is honestly kinda insane.

user

10 hours ago

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