Fix: do not flag Roboto in system font stacks (#678)

Treat the leading system face as primary so later Roboto fallbacks do not trigger overused-font, while named web-font primaries still flag.

AI-assisted merge: reviewed and executed by Codex under maintainer direction.
This commit is contained in:
Abdul Wahab
2026-08-31 19:20:51 -04:00
committed by GitHub
parent 205643cf7a
commit 2cfd60765a
7 changed files with 192 additions and 30 deletions
+24 -13
View File
@@ -70,13 +70,27 @@ function isBrandFontOnOwnDomain(font) {
return allowed.some(suffix => host === suffix || host.endsWith('.' + suffix));
}
const GENERIC_FONTS = new Set([
// Overused-font primary selection skips only CSS generics so a system stack
// keeps the system face as primary; GENERIC_FONTS still includes platform
// faces for design-system/serif resolution.
const CSS_GENERIC_FONTS = new Set([
'serif', 'sans-serif', 'monospace', 'cursive', 'fantasy',
'system-ui', 'ui-serif', 'ui-sans-serif', 'ui-monospace', 'ui-rounded',
'-apple-system', 'blinkmacsystemfont', 'segoe ui',
'inherit', 'initial', 'unset', 'revert',
]);
const GENERIC_FONTS = new Set([
...CSS_GENERIC_FONTS,
'system-ui', 'ui-serif', 'ui-sans-serif', 'ui-monospace', 'ui-rounded',
'-apple-system', 'blinkmacsystemfont', 'segoe ui',
]);
function primaryFontFace(fontFamily, skip = CSS_GENERIC_FONTS) {
return String(fontFamily || '')
.split(',')
.map(f => f.trim().replace(/^['"]|['"]$/g, '').toLowerCase())
.find(f => f && !skip.has(f)) || null;
}
// WCAG large text thresholds are defined in points: 18pt normal text and
// 14pt bold text. Browsers expose font-size in CSS pixels at 96px per inch.
const WCAG_LARGE_TEXT_PX = 18 * (96 / 72);
@@ -1591,7 +1605,7 @@ function checkIconTile(opts) {
function resolveSerif(fontFamily) {
if (!fontFamily) return { primary: null, isSerif: false };
const tokens = fontFamily.split(',').map(f => f.trim().replace(/^['"]|['"]$/g, '').toLowerCase());
const primary = tokens.find(f => f && !GENERIC_FONTS.has(f)) || null;
const primary = primaryFontFace(fontFamily, GENERIC_FONTS);
if (!primary) return { primary: null, isSerif: false };
if (KNOWN_SERIF_FONTS.has(primary)) return { primary, isSerif: true };
if (tokens.includes('serif')) return { primary, isSerif: true };
@@ -5190,8 +5204,7 @@ function checkTypography() {
const style = getComputedStyle(el);
const ff = style.fontFamily;
if (!ff) continue;
const stack = ff.split(',').map(f => f.trim().replace(/^['"]|['"]$/g, '').toLowerCase());
const primary = stack.find(f => f && !GENERIC_FONTS.has(f));
const primary = primaryFontFace(ff);
if (!primary) continue;
fontUsage.set(primary, (fontUsage.get(primary) || 0) + 1);
totalTextElements++;
@@ -5436,8 +5449,7 @@ function checkPageTypography(doc, win) {
if (rule.type !== 1) continue;
const ff = rule.style?.fontFamily;
if (!ff) continue;
const stack = ff.split(',').map(f => f.trim().replace(/^['"]|['"]$/g, '').toLowerCase());
const primary = stack.find(f => f && !GENERIC_FONTS.has(f));
const primary = primaryFontFace(ff);
if (primary) {
fonts.add(primary);
if (OVERUSED_FONTS.has(primary)) overusedFound.add(primary);
@@ -5456,11 +5468,10 @@ function checkPageTypography(doc, win) {
const ffRe = /font-family\s*:\s*([^;}]+)/gi;
let fm;
while ((fm = ffRe.exec(html)) !== null) {
for (const f of fm[1].split(',').map(f => f.trim().replace(/^['"]|['"]$/g, '').toLowerCase())) {
if (f && !GENERIC_FONTS.has(f)) {
fonts.add(f);
if (OVERUSED_FONTS.has(f)) overusedFound.add(f);
}
const primary = primaryFontFace(fm[1]);
if (primary) {
fonts.add(primary);
if (OVERUSED_FONTS.has(primary)) overusedFound.add(primary);
}
}