@Body() don't transfer body object to dto object

I’m submitting a…

[ ] Regression 
[x] Bug report
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

@Controller()
export class ApiController {
  @Post()
  async index(@Body() body: BodyDTO) {
     // `body` is not a BodyDTO, just a normal object
     console.log(body instanceof BodyDTO) // false
  }
}

Expected behavior

@Controller()
export class ApiController {
  @Post()
  async index(@Body() body: BodyDTO) {
     console.log(body instanceof BodyDTO) // true
  }
}

What is the motivation / use case for changing the behavior?

Sometimes, I need to do something with dto object.

class BodyDTO {
  readonly firstName: string
  readonly lastName: string
  get name(): string { return this.firstName + ' ' + this.lastName }
}

It’s not convenience without dto object. And it’s not a intuitive way.

Environment

Nest version: 4.6.6

 
For Tooling issues:
- Node version: 9.11.1  
- Platform:  Mac 

[XGHeaven]

@unlight Thanks

It works for me.

// ...
async index(@Body(new ValidationPipe({transform: true})) body: BodyDTO) {
  console.log(body instanceof BodyDTO) // true
}
// ...

I suggest updating docs.

[unlight]

Transforming plain object to specific class is not applying automatically. You need to use pipes (see docs) You can write your own, or you can use built-in pipe ValidationPipe.