pub fn check_touch_density(js_dir: impl AsRef<Path>)Expand description
Fail the build if a JS copy of the touch-density query has drifted from
Density::Touch.
Every .js file under js_dir, recursively, must state the crate’s own
media condition in a const TOUCH_DENSITY = '...', at least one file must
declare it, and no file may name a capability sniff.
The string is the crate’s and no app gets a say in it, which is why this
check takes no policy argument. The generated geometry.css already keys
its touch gap overrides on the same condition, so the gestures and the
spacing agree by construction rather than by two people remembering.
Emits cargo:rerun-if-changed for every file it read.
§Panics
If js_dir cannot be read, if no declaration is found, or if any file
disagrees with the crate. A build script has nowhere useful to return an
error to, and a frontend that disagrees with its own stylesheet is worse
than a failed build.