Iosevka/tools/misc/src/make-webfont-css.mjs

import fs from "node:fs";

const WebfontFormatMap = new Map([
	["WOFF2", "woff2"],
	["TTF", "truetype"],
]);

export default function (output, family, hs, formats, unhinted) {
	if (!formats) {
		fs.writeFileSync(output, "");
		return;
	}
	let ans = ``;
	for (const ext of formats) {
		if (!WebfontFormatMap.get(ext)) throw new TypeError(`Invalid webfont file format ${ext}`);
	}
	for (const term of hs) {
		const dirSuffix = unhinted ? "-Unhinted" : "";
		const src = formats
			.map(
				ext =>
					`url('${ext}${dirSuffix}/${term.name}.${ext.toLowerCase()}') ` +
					`format('${WebfontFormatMap.get(ext)}')`,
			)
			.join(", ");
		ans += `
@font-face {
	font-family: '${`${family} Web`}';
	font-display: swap;
	font-weight: ${term.css.weight};
	font-stretch: ${term.css.stretch};
	font-style: ${term.css.style};
	src: ${src};
}
`;
		if (term.css.style === "oblique") {
			// CHROME hates a family with both Italic and Oblique
			ans += `
@font-face {
	font-family: '${`${family} Web Oblique`}';
	font-display: swap;
	font-weight: ${term.css.weight};
	font-stretch: ${term.css.stretch};
	src: ${src};
}
`;
		}
	}
	fs.writeFileSync(output, ans);
}