Next.js: Оптимизация шрифтов — типичные gotcha на собеседовании

size-adjust fallback не только swap, zero Google runtime, subsets, module scope loader, explicit weight, preload scope — типичные вопросы.

Разбор

• «How avoid font layout shift?» Metric-matched size-adjust @font-face, не только display: swap. Swap без matched metrics still reflows.
• next/font/google zero runtime Google requests. Self-host at build — GDPR fix too, не proxy <link>.
• Forgetting subsets ships all language glyphs — huge file. Always subset.
• Font loader inside component vs module scope — re-triggers work, breaks optimization.
• Non-variable fonts need explicit weight. Omitting = common miss.
• preload only fonts used on current route. Font declared but used deep rare route — not preloaded elsewhere (usually desired).

Итог

Senior font answer = size-adjust mechanics + build-time self-host + module-level declaration.