A clean way to check for query parameter in NestJS

Question

I have a nestjs project that is mostly in RESTful structure. Everything works fine, but my concern is that some of the routes check for the presence of some query parameters to fetch data. for instance

@Get('/some-resources')
async getSomeResource(
  @Query() query: any
): Promise<HTTPResponseDTO>{
 const startDate = query.startDate ? DateTime.fromISO(query.startDate).startOf('day').toISO(): null;
 const endDate = query.endDate ? DateTime.fromISO(query.endDate).endOf('day').toISO() : null;
.
.
.
const result = await this.someResourceService.findAll(startDate, endDate,...)
}

Now my question is, is there a cleaner approach to this? Because this can get become a pain to maintain when we have many resources.

Answer 1

As mentioned by Micael Levi, you should be able to do this by creating your own custom pipe. Assuming that what you posted works, you should be able to do something along the lines of:

@Get('/some-resources')
async getSomeResource(
  @Query('startDate', ParseDateIsoPipe) startDate?: string, 
  @Query('endDate', ParseDateIsoPipe) endDate?: string
): Promise<HTTPResponseDTO>{
 <code>
}

With your ParseDateIsoPipe as follows (Note that you will still need to import DateTime from the package you are using):

import { PipeTransform, Injectable, ArgumentMetadata } from '@nestjs/common';

@Injectable()
export class ParseDateIsoPipe implements PipeTransform {
  transform(value: any, metadata: ArgumentMetadata) {
    return value ? DateTime.fromISO(value).startOf('day').toISO(): null;
  }
}