Sometimes you want to create a subset of a font with characters you know you need, e.g. Latin.
But maybe every once in a while you need a character or two you missed from the complete font.
So how about having a second subset containing everything that is NOT in the initial subset.
Using unicode ranges you can load the main subset and then, only when needed, get the additional subset.
Glyphhanger and its prerequisites, see here
https://github.com/zachleat/glyphhanger/
npm i -g inverse-subset
$ which inverse-subset
/usr/local/bin/inverse-subset
$ node /usr/local/bin/inverse-subset -h
Usage: inverse-subset [options]
Generates an inverse subset font from a complete font and a subset font.
Options:
-V, --version output the version number
-c, --complete <path> Path to the complete font file
-s, --subset <path> Path to the subset font file
-o, --output <directory> Directory for the inverse subset font (default: "/Users/you/Documents/codez")
-h, --help display help for command
$ node /usr/local/bin/inverse-subset -c ../Oxanium.ttf -s ../subset/Oxanium-subset.woff2
Creating the inverse subset...
Running: glyphhanger --formats=woff2 --subset="../Oxanium.ttf" --whitelist=U+0,U+D,U+A0,U+A1,U+A2,U+A3,U+A4,U+A5,U+A6,U+A7,U+A8,U+A9,U+AA,U+AB,U+AC,U+AD,U+AE,U+AF,U+B0,U+B1,U+B2,U+B3,U+B4,U+B5,U+B6,U+B7,U+B8,U+B9,U+BA,U+BB,U+BC,U+BD,U+BE,U+BF,U+C0,U+C1,U+C2,U+C3,U+C4,U+C5,U+C6,U+C7,U+C8,U+C9,U+CA,U+CB,U+CC,U+CD,U+CE,U+CF,U+D0,U+D1,U+D2,U+D3,U+D4,U+D5,U+D6,U+D7,U+D8,U+D9,U+DA,U+DB,U+DC,U+DD,U+DE,U+DF,U+E0,U+E1,U+E2,U+E3,U+E4,U+E5,U+E6,U+E7,U+E8,U+E9,U+EA,U+EB,U+EC,U+ED,U+EE,U+EF,U+F0,U+F1,U+F2,U+F3,U+F4,U+F5,U+F6,U+F7,U+F8,U+F9,U+FA,U+FB,U+FC,U+FD,U+FE,U+FF,U+100,U+101,U+102,U+103,U+104,U+105,U+106,U+107,U+10C,U+10D,U+10E,U+10F,U+110,U+111,U+112,U+113,U+116,U+117,U+118,U+119,U+11A,U+11B,U+11E,U+11F,U+122,U+123,U+12A,U+12B,U+12E,U+12F,U+130,U+131,U+136,U+137,U+139,U+13A,U+13B,U+13C,U+13D,U+13E,U+141,U+142,U+143,U+144,U+145,U+146,U+147,U+148,U+14C,U+14D,U+150,U+151,U+152,U+153,U+154,U+155,U+156,U+157,U+158,U+159,U+15A,U+15B,U+15E,U+15F,U+160,U+161,U+162,U+163,U+164,U+165,U+16A,U+16B,U+16E,U+16F,U+170,U+171,U+172,U+173,U+178,U+179,U+17A,U+17B,U+17C,U+17D,U+17E,U+192,U+218,U+219,U+21A,U+21B,U+237,U+2C6,U+2C7,U+2C9,U+2D8,U+2D9,U+2DA,U+2DB,U+2DC,U+2DD,U+300,U+301,U+302,U+303,U+304,U+306,U+307,U+308,U+30A,U+30B,U+30C,U+326,U+327,U+328,U+3C0,U+1E9E,U+2013,U+2014,U+2018,U+2019,U+201A,U+201C,U+201D,U+201E,U+2020,U+2021,U+2022,U+2026,U+2030,U+2039,U+203A,U+2044,U+2070,U+2074,U+2080,U+2081,U+2082,U+2083,U+2084,U+20AC,U+20BA,U+20BD,U+2113,U+2122,U+2126,U+212E,U+2202,U+2206,U+220F,U+2211,U+2212,U+2215,U+2219,U+221A,U+221E,U+222B,U+2248,U+2260,U+2264,U+2265,U+25CA,U+F000,U+FB01,U+FB02
Created: /Users/you/Documents/codez/Oxanium-inverse-subset.woff2
Inverse subset generation complete.
Because Glyphhanger always uses -subset in the name, the new subset generated by this script will have this name temporarily before moved to the -o directory.
If you've just created a -subset with Glyphhanger in the same directory, it will be overwritten as a result of this script, so please rename it first or move it to a different directory.
For an announcement and more on Unicode ranges, including some test pages, see https://www.phpied.com/inverse-font-subsetting/