Remix display runtime errors using the <ErrorBoundary> export.
This template includes a default component that handles both Error and thrown Response.
It also includes helper functions in utils/responses for handling typical errors like page not found, bad request, etc.
There is a test /error route that shows how these helpers are used.
For example:
// renders the `<BadRequest>` component
// and displays the errors in a list
throw badRequest('Bad Request', [
'missing param',
'value must be number',
'etc',
])