In order to detect if font contains some particular character in javascript I've decided that the best way is to have fallback font where ALL unicode characters have exactly ZERO width spaces. This font would allow me to easily check existing of himself, and existing of any character in any other font (except for conrtol characters). I would just check width of character.
Do you know if such font already exists?
It should be very simple to make it with FontForge and scripting. But it is hard for me to get into FontForge and Unicode docs. If someone is fluent in FontForge, could you teach me, or just make this kind of font. I assume it is, what, like 50 script lines on Python?
https://github.com/adobe-fonts/adobe-blank – answered by Mike 'Pomax' Kamermans
Very nice. Just 7kb for woff version! My own attempts to make such a font myself in FontForge gave about 1mb for 0000-1ffff unicode range.