Hacker News Reader

Comment by chrismorgan | Hacker News Reader

  @media (max-width: 479.98px)

This would be more accurately expressed with negation (though the difference will probably never matter to even a single human):

  @media not all and (min-width: 480px)

This is using widest-compatible syntax, since WebKit only very recently (Safari 16.4) got the Media Queries Level 4 stuff to let you write it in clearer ways. The “not” applies to the remainder of the query: parse it as “not (all and (min-width: 480px))” rather than “(not all) and (min-width: 480px)” which would never match.

(As far as I can tell, compatibility charts don’t show this Level 4 query syntax boolean logic stuff at all. Anyone want to do me a favour and file MDN data bug about it? If you do, mention it because otherwise I might finally get round to reporting it later.)

View on HN

You should mention that new stuff, so that people know what to look forward to.

@media (width < 480px)

The article already mentioned that.

There's no need to mess with the breakpoints. They're chosen carefully. The article explains why this one works optimally:

> Why 0.98px specifically? 0.02px is the smallest division of a CSS pixel that an earlier version of Safari supported. See WebKit bug #178261.

You shouldn't need arcane knowledge of Safari bugs to evaluate a simple media query. This will break on first encounter with a well intentioned maintainer. The option with the least outside knowledge required is usually the most robust choice I feel.

I’m confused by your defensiveness. What I express has the same browser support, but is correct (rather than leaving a tiny gap that is theoretically possible to encounter, though vanishingly improbable in reality), doesn’t depend on esoteric knowledge of the meaning of a 0.02px difference, and sticks with just the one magic number which is obviously desirable for various maintenance purposes. On the downside, “not all and (min-width: 480px)” is an idiosyncratic spelling, and you run the risk of people reaching for “not (min-width: 480px)” instead, which works in current browsers but sheds support for somewhat older browsers (with Safari being the last to get it, only a couple of months ago).

(In the wild, I’ve encountered exact-value overlap, which is obviously wrong and very easy to trigger, −1px, which is obviously wrong and fairly easy to trigger, −0.1px which is fairly safe, and −0.01px, but I don’t recall ever encountering −0.02px.)

If the article had used a negated media query, would you be arguing for using a non-negated .98?

The CSS Media Queries Level 4 spec actually includes fractional pixel values as part of the examples for browsers which do not yet support the range syntax: https://www.w3.org/TR/mediaqueries-4/#mq-min-max

> One approach to work around this problem is to increase the precision of the values used for the comparison. Using the example above, changing the second comparison value to 320.01px significantly reduces the change that a viewport width on a device would fall between the cracks.

The .02/.98 values might seem strange, but many popular libraries use these offsets (including Bootstrap: https://github.com/twbs/bootstrap/blob/main/scss/mixins/_bre...).

The way I tend to work with media queries is not writing them directly but rather use a mixin (when using SCSS) or a media function (CSS-in-JS). That way, this weird quirk can be documented just once in an application, leaving anyone curious enough with the explanation. There tends to be an 'upTo(breakpoint)' function which is an exclusive range, and a 'from(breakpoint)' which is inclusive.

If you have only one clause, using a negated clause is strictly superior. The only reason to go fractional is if you have multiple clauses, since Level 3 only supported negation of the entire thing. I think that’s why using negation has never been particularly common, because people sometimes like to basically do `(width >= 480px) and (width < 768px)`. (In my experience, you’re normally better stacking the queries—e.g. mobile default, then (min-width: 480px), then (min-width: 768px)—rather than attempting to apply them exclusively, though there are certainly sometimes reasons to do it otherwise.)

> I’m confused by your defensiveness

It's because you say something is superior, and that "not all and (min-width: 480px)" negation syntax is by any programming language standard unreadable. The .98 thing is terrible too, but for me, I don't like when I can't easily parse using parens and PEMDAS. I don't think there is a single correct answer so I felt the need to point out that the breakpoints you disagree with are fine. I think it's fine if you use something else in your code but I don't really want the authors of frameworks I use to move over to "not all and X" that is really "not (all and X).

Yes, "not" is better than fractions.

Reply on news.ycombinator.com