@prairielearn/trpc

Shared tRPC infrastructure for PrairieLearn applications. Import from an explicit subpath so that browser builds cannot pull in server-only dependencies.

| Subpath | Public API | | ---------------------------- | -------------------------------------------------------------------- | | @prairielearn/trpc/server | appErrorFormatter, throwAppError, and application-error types | | @prairielearn/trpc/client | AppError, AppErrorRenderers, getAppError, and renderAppError | | @prairielearn/trpc/react | AppErrorAlert and QueryClientProviderDebug | | @prairielearn/trpc/express | isTrpcRequest, isMultipartRequest, and formatTrpcErrorResponse |

Typed error maps

The server and client intentionally resolve a whole procedure error map differently:

• throwAppError<WholeErrorMap> accepts only variants shared by every procedure. This prevents a helper that can run for every procedure from throwing an error that some procedures did not declare.
• getAppError<WholeErrorMap> returns the union of all procedure variants. This supports a client component that handles failures from several procedures.

For a single procedure, pass its map entry to either helper, such as throwAppError<WidgetError['Update']>(...) or getAppError<WidgetError['Update']>(error).

Express errors before the adapter

formatTrpcErrorResponse builds the SuperJSON-wrapped tRPC error response used when authentication, authorization, CSRF, or other Express middleware fails before the tRPC adapter runs. Its numeric JSON-RPC code is sourced from tRPC's own TRPC_ERROR_CODES_BY_KEY constants.

Error IDs generated for normal Express errors and adapter errors remain server-side and correlate application logs with error reporting. The shared response shape does not expose an error ID to clients.