Route and layout fallbacks

Route-local fallback

const route = defineRoute({
  id: 'reports',
  path: '/reports',
  view: ReportsPage,
  loading: ReportsLoading,
  error: ReportsError,
});

Route loading and error are renderer-neutral route fields. They apply to that route and are not inherited by descendants.

Layout fallback

const route = defineRoute({
  id: 'app',
  path: '/app',
  layout: {
    view: AppLayout,
    loading: AppLoading,
    error: AppError,
  },
  children: [/* ... */],
});

Layout fallbacks belong to the active layout boundary and can cover descendant rendering. Declaring layout.loading or layout.error without an active layout view is a validation error.

Global provider fallback

Use RouterProvider fallbacks for application-wide startup or uncaught route-tree failures. They are not a substitute for a local boundary when only one route or slot should disappear.

Where this bites

errorFallback was removed from route and layout declarations. Use error. Slot still has its own errorFallback prop because slot isolation is a React rendering concern, not a route-definition fallback.