FRONT008warningPro

loading-returns-null

Returning null during loading causes layout shift and flash of empty content.

Applies to: JavaScript, TypeScript

Why this matters

When a component returns null while loading, it renders nothing — causing the layout to shift when content appears. This is jarring for users and can hurt CLS (Cumulative Layout Shift) scores. Return a skeleton or placeholder instead.

Catch it before it ships

pip install stablestack # or: npx stablestackstablestack # scans your project, FRONT008 includedstablestack explain FRONT008

FRONT008 is part of the Pro rule set. See pricing — the free tier ships 24 checks with no signup.

False positive in your codebase? Suppress a single line with # noqa: FRONT008

More Frontend checks

FRONT001

tabs-url-routing

MUI Tabs should use URL routing via useSearchParams for bookmarkable/shareable tabs.

FRONT002

window-ssr-unsafe

Accessing window/document without SSR check causes server-side errors

FRONT003

inline-jsx-handler

Inline arrow functions in JSX cause unnecessary re-renders

FRONT004

nextjs-redirect-request-url

Redirect uses request.url as URL base, which is wrong behind a reverse proxy.

FRONT005

useeffect-side-effect-unguarded

useEffect contains a mutating HTTP call without a guard against double-firing.

FRONT006

stale-time-dependent-ui

Time-dependent filtering without a re-render timer will show stale data.

FRONT007

unbounded-ai-output

AI/LLM output rendered in JSX without truncation or overflow handling.

FRONT009

eager-queries-no-defer

3+ query hooks all firing on mount with no deferred loading.