在Nest JS中导入dto类

Question

I'm trying to use a DTO to define my data for my controller within Nest.js.

I am following the tutorial

I have created my DTO within src/controllers/cats/dto/create-cat.dto.js

export class CreateCatDto {
  readonly name: string;
  readonly age: number;
  readonly breed: string;
}

I am confused as to how this gets imported into the application though. The documentation doesn't actually state that it needs to be imported so I assumed nest is doing some magic behind the scenes? All though I have a feeling this isn't the case.

I am trying to import it directly in my controller:

import { CreateCatDto } from './dto/create-cat.dto';

But this throws an error:

Unexpected token (2:11)
  1 | export class CreateCatDto {
> 2 |   readonly name: string;
    |            ^
  3 |   readonly age: number;
  4 |   readonly breed: string;
  5 | }

The DTO code is ripped directly off the nest docs so there shouldn't be an ussue with the code (all though readonly name: string; doesn't look like javascript I have come across before).

For reference, here is the rest of my cat Controller where I am trying to use the DTO

import { Controller, Bind, Get, Post, Body, Res, HttpStatus } from '@nestjs/common';
// import { CreateCatDto } from './dto/create-cat.dto';

@Controller('cats')
export class CatsController {

  @Post()
    @Bind(Res(), Body())
    async create(res, body, createCatDto) {
        console.log("createCatDto", createCatDto)
        res.status(HttpStatus.CREATED).send();
    }

  @Get()
  findAll() {
    return [];
  }
}

Does the DTO class need to be imported and then use bind to my create function like Res() and Body() or does nest do some magic behind the scene since they never state to import it in there docs?

Thanks.

Answer 1

Quick Answer: You can't use DTO in JavaScript ES6

Not So Long Answer: Here is an excerpt from the docs, just has DTO was introduced.

Firstly, we need to establish the DTO (Data Transfer Object) schema. A DTO is an object that defines how the data will be sent over the network. We could do this by using TypeScript interfaces, or by simple classes.

As you can see, it was used there as an interface to provide Static typing . You really can't utilize DTOs in JS because interface and Static typing are not part of ES6 standards.

You should skip the DTO part for ES6 and use the @Body() argument like this instead

@Post()
@Bind(Body())
async create(createCatDto) {
    // TODO: Add some logic here
}

My Advice: Try considering moving to Typescript to take full advantage of NestJS.