Error handling

The library throws standard NestJS HTTP exceptions, so they render through your app's exception filter like any other. The default body shape is:

{ "statusCode": 400, "message": "…", "error": "Bad Request" }

For validation errors, message is an array of strings.

Status codes

Status	When
200 OK	successful read, update, delete, restore
201 Created	successful create / createMany
400 Bad Request	invalid input (see below)
404 Not Found	findOne / update / delete / restore / trash on a missing row

What raises 400

• Malformed JSON in where / relations / order / select / aggregates / having.
• An unknown filter field in where (only real columns and relation paths are allowed).
• An unknown order key — a column/alias the query doesn't expose. (Unknown order keys are rejected rather than silently ignored; see Migration.)
• A hidden field (@CrudHidden() / hiddenFields) named in where / order / relations / an aggregate field. The error is identical to "unknown field" so the field's existence isn't revealed.
• An unsupported operator, e.g. a typo like $gtt.
• $in / $notIn / $inL / $notinL given a non-array value.
• $between / $notBetween not given a [start, end] pair.
• An aggregate with an invalid field (must be a relation path like posts.id), a bad as alias (must match ^[A-Za-z_][A-Za-z0-9_]*$), or one colliding with a real column.
• A having key that isn't a defined aggregate alias.
• take (page size) greater than maxPerPage.
• An invalid groupByKey on counts.
• An empty body on create.
• Postgres-only operators ($contArr, $intersectsArr) on a non-Postgres database.
• Any failure from your DTO / class-validator rules (when validation is enabled).

What raises 404

findOne, update, delete, restore, and deleteFromTrash throw NotFoundException when no row matches the id/criteria.

Customising errors

Catch and reshape these with a standard NestJS exception filter. All exceptions are HttpException subclasses (BadRequestException, NotFoundException), so a global filter can map them to your own envelope.

The Swagger document already includes reusable ErrorResponseDto and ValidationErrorResponseDto schemas for these responses.