NestJs one Post request with relation - nestjs

Question

In my NestJs app I have two entities: person.entity.ts and property.entity.ts, the two are connected with OneToMany relation. I have created DTOs for both person and property.
The owning side of the relation is defined in Person like this:
#JoinColumn()
#OneToMany(
(type) => PersonProperties,
(personProperties) => personProperties.person,
{ cascade: ['insert', 'update'] },
)
personProperties: PersonProperties[];
My Controller for posting new Person looks like this:
#Post()
async create(#Body() createPersonDto: CreatePersonDto) {
return this.personService.create(createPersonDto);
}
For validation I am using Global ValidationPipes as below:
async function bootstrap() {
const app = await NestFactory.create(AppModule);
app.useGlobalPipes(
new ValidationPipe({
whitelist: true,
forbidNonWhitelisted: true,
transform: true,
transformOptions: {
enableImplicitConversion: true,
},
}),
);
How should I modify my code so I can post (and validate) a Person with their properties with a single Request? Isn't this going to include one DTO inside another?

Answer 1

What you must use are Pipes Read more about it
In your case, a Validation Pipe is required to validate the incoming request against your DTO.
Pipes are used inside a controller, though you can read about creating custom pipes inbuilt ValidationPipe would satisfy your needs for now.
METHOD 1
#Post()
async create(#Body(ValidationPipe) createPersonDto: CreatePersonDto) {
return this.personService.create(createPersonDto);
}
METHOD 2
#Post()
#UsePipes(ValidationPipe)
async create(#Body() createPersonDto: CreatePersonDto) {
return this.personService.create(createPersonDto);
}
Both methods essentially do the same thing. It takes your Body request object and validates it against your defined DTO.
Hope this answers your question.

Answer 2

The solution is to create a composite DTO object as follows:
export class CreatePersonWithPropertiesDto {
#ValidateNested()
#Type(() => CreatePersonDto)
neuron: CreatePersonDto;
#IsOptional()
#ValidateNested({ each: true })
#Type(() => CreatePersonPropertiesDto)
personProperties?: CreatePersonPropertiesDto[];
}
and then adjust the controller to expect the composite DTO:
#Post()
async create(#Body() createPersonWithPropertiesDto: CreatePersonWithPropertiesDto) {
return this.personService.create(createPersonWithPropertiesDto);
}