How to pass a Date in url param and how to validate it with class-validator?

Question

I'm trying to validate a date param (with class-validator) in my Nest.js api; below is what I have:

class DateValidate {
  @IsDate()
  date: Date;
}

  @Get('day/:day')
  getDayMealsPlan(@Param('day') day: DateValidate): any {
    return day;
  }

I'm passing the date param in the URL like so:

localhost:3000/meals/day/2022-03-06T11:00:00.000Z

It's throwing me a 400 error:

{
    "statusCode": 400,
    "message": [
        "date must be a Date instance"
    ],
    "error": "Bad Request"
}

I have a 2 part question:

1. How to validate a date?
2. How would a date look in the param? Is this the right way to do it: 2022-03-06T11:00:00.000Z

Answer 1

2022-03-06T11:00:00.000Z this value is a String type. That's why class-validator is complaining not Date instance.

You need to tell to transform your string format to Date.

You can achieve that using Type decorator from class-transformer.

class DateValidate {
  @IsDate()
  @Type(() => Date)
  day: Date;
}

@Controller('something')
export class SomethingController {
  @Get('day/:day')
  getDayMealsPlan(@Param() params: DateValidate) {
    console.log(params.day instanceof Date); // true
    return params;
  }
}