@next/font
Version:
`@next/font` includes built-in automatic self-hosting for any font file. This means you can optimally load web fonts with zero layout shift, thanks to the underlying CSS size-adjust property used.
36 lines (35 loc) • 1.56 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.findFontFilesInCss = void 0;
/**
* Find all font files in the CSS response and determine which files should be preloaded.
* In Google Fonts responses, the @font-face's subset is above it in a comment.
* Walk through the CSS from top to bottom, keeping track of the current subset.
*/
function findFontFilesInCss(css, subsetsToPreload) {
var _a, _b;
// Find font files to download
const fontFiles = [];
// Keep track of the current subset
let currentSubset = '';
for (const line of css.split('\n')) {
const newSubset = (_a = /\/\* (.+?) \*\//.exec(line)) === null || _a === void 0 ? void 0 : _a[1];
if (newSubset) {
// Found new subset in a comment above the next @font-face declaration
currentSubset = newSubset;
}
else {
const googleFontFileUrl = (_b = /src: url\((.+?)\)/.exec(line)) === null || _b === void 0 ? void 0 : _b[1];
if (googleFontFileUrl &&
!fontFiles.some((foundFile) => foundFile.googleFontFileUrl === googleFontFileUrl)) {
// Found the font file in the @font-face declaration.
fontFiles.push({
googleFontFileUrl,
preloadFontFile: !!(subsetsToPreload === null || subsetsToPreload === void 0 ? void 0 : subsetsToPreload.includes(currentSubset)),
});
}
}
}
return fontFiles;
}
exports.findFontFilesInCss = findFontFilesInCss;