react-doctor/no-locale-format-in-render

Locale/timezone formatting during render

• Category: Bugs
• Severity: warn
• Source: oxlint-plugin-react-doctor
• Framework: global
• Enabled when: react, ssr
• Default: Enabled

Validation prompt

Use this to decide whether a fired diagnostic is real or a false positive.

Confirm the reported code matches Locale/timezone formatting during render. Check the framework context and diagnostic message before suppressing it.

Fix prompt

Use this once validation confirms the diagnostic is real.

Format locale/timezone-dependent values in a post-mount useEffect + state, or pass an explicit locale and timeZone so the server and the browser render the same text. Only runs on SSR-capable projects.

Related rules

More Bugs rules from the rules reference:

• react-doctor/no-match-media-in-state-initializer: matchMedia in state initializer
• react-doctor/no-mirror-prop-effect: Delete both the `useState` and the `useEffect` and read the prop directly during render. Mirroring a prop into local state forces a stale first render before the effect re-syncs
• react-doctor/no-mutable-in-deps: Read mutable values (`location.pathname`, `ref.current`) inside the effect body instead of in the deps array, or subscribe with `useSyncExternalStore`. Mutations to these don't trigger re-renders, so listing them in deps doesn't make the effect react to changes
• react-doctor/no-mutating-reducer-state: Return a new reducer state object/array/collection instead of mutating the current state and returning the same top-level reference.
• react-doctor/no-namespace: Drop the namespace and use a plain (Pascal-cased) component or DOM tag.