I suspect it won’t be that straightforward, awesome library btw!
I tried to find out the length if I had to put all the ranges in CSS, and it is arguably okay (especially with gzip/brotli) if the script isn’t common or arabic.
[
common: 2363,
arabic: 781,
ethiopic: 474,
latin: 471,
greek: 450,
inherited: 385,
han: 276,
grantha: 223,
tamil: 204,
hangul: 180,
katakana: 179,
...
]
So mapping a language code to the right scripts to the right code points is not a trivial exercise.
Indeed. However, unless OP is creating their own font subsets, it is not necessary to check the relationship between scripts and codepoints (Noto variants did that for us), and the list of glyphs available in each font file can be used instead to generate the list of codepoint ranges, which I imagine could be automated with a FontForge script. Then I remembered where I first see this CSS attribute: Google Fonts. The CSS files they provide already have codepoint ranges for the fonts they offer:
