Nuxtjs Guideline: State — Use useState for shared reactive state. Description: SSR-friendly shared state across components. Do: useState for cross-component state. Don't: ref for shared state. Good Example: const count = useState('count', () => 0). Bad Example: const count = ref(0) in composable. Severity: High. Docs: https://nuxt.com/docs/api/composables/use-state.