Just the first example "Device type in JS".
"A coarse pointer does not mean “mobile”, and a fine pointer does not guarantee “desktop”. Ask the browser about input capabilities instead of guessing the device from its user agent."
const input = {
finePointer: matchMedia('(any-pointer: fine)').matches,
coarsePointer: matchMedia('(any-pointer: coarse)').matches,
canHover: matchMedia('(any-hover: hover)').matches,
};
So it doesn't tell me how to identify device type. It doesn't even run the code so I could quickly compare results between my mobile and desktop devices to establish a baseline.