router-core/not-found-and-errors

Handle 404 not found errors in TanStack Router by configuring notFoundComponent and defaultNotFoundComponent to display custom pages for unmatched routes and missing resources.

Route masking in TanStack Router shows alternate URLs without changing the rendered route by calling createRouteMask, optionally unmasking on reload to reveal the true path.

NotFoundMode settings in TanStack Router control how unmatched routes are resolved: fuzzy attempts partial route resolution, while root mode strictly falls back to the root not-found component.

Set up global error boundaries in TanStack Router by defining errorComponent configurations that display friendly messages and allow retrying data fetching via router.invalidate().

Trigger a custom 404 page from a TanStack Router loader by calling the notFound() function inside the route loader to signal missing data and render the configured notFoundComponent.

Avoid deprecated NotFoundRoute and unsafe data access in TanStack Router because they bypass modern notFoundMode and errorComponent boundaries, causing inconsistent error handling and runtime crashes.