@nestjs-automapper/typeorm

TypeORM schema adapter. Lets a DTO derive its own select and relations.

pnpm add @nestjs-automapper/typeorm

Peer: typeorm ^1.1.1.

Usage

import { typeorm } from '@nestjs-automapper/typeorm';

const mapper = new Mapper().use(typeorm(dataSource));

That is the whole setup. Entities need no mapping decorators — the adapter reads the metadata TypeORM already has.

Projection

const find = mapper.nativeProjectionFor(ReadUserDto) as FindManyOptions<User>;
// { select: { id: true, email: true, firstName: true, lastName: true } }

await repo.find(find);

A twenty-column entity behind a five-field DTO issues a five-column SELECT. Relations the DTO never touches are not joined.

The primary key is added even when the DTO omits it — TypeORM needs it to hydrate relations and dedupe rows. That happens here rather than in core, so the neutral selection keeps reporting only what the DTO consumes.

What it reads

| TypeORM | Used for | |---|---| | column.propertyName | the field name, verbatim | | column.databaseName | translation and did-you-mean only | | column.type, enum | JSON/OpenAPI types and enum values | | isNullable | nullability, and OpenAPI required | | isPrimary, isGenerated | write drop list, projection keys | | isCreateDate, isUpdateDate, isDeleteDate | write drop list | | isVersion, isDiscriminator | write drop list | | isSelect | hidden on read — not a write drop reason | | relation.joinColumns, relationType | relations and foreign keys |

isSelect: false is the password case: excluded from implicit expansion, still nameable, and always writable. Treating it as database-owned would make it impossible to ever set one.

Notes

• describe() returns everything the schema declares and applies no policy. Filtering is the planner's job.
• supports() never throws, so adapter arbitration stays predictable.
• Entity schemas defined as plain objects (rather than classes) are not supported; relations need a class target.
• A string | null column needs an explicit type — TypeScript reflects the union as Object, which TypeORM cannot map. That is true of TypeORM generally, not something this adapter adds.

License

MIT