I'm facing same problem.

Can't believe NestJS doesnt have a built-in validator for this.

Checking against database is a very basic stuff. I ended with a solution similar to yours, however, I'm stuck with PUT requests.

When you apply a IsUnique validation in a PUT request, you must 'ignore' the affected row from database check.

For example: The user with id 'some-id' does a PUT to users/some-id With data:

{
  name: 'some-edited-name', // modified data
  email: '[email protected]', // didn't modify email
}

Here the validator will fails because it's detecting '[email protected]' already exists in database. In this case, validator should ignore the id with 'some-id' value. But I don't know how to achieve it :(

I would like to have something like this:

export class UpdateExerciseTypeDto {
  /* identity data */
  @ApiProperty()
  @IsNotEmpty()
  @IsString()
  @IsUnique(ExerciseType, { ignore: 'id' }) // something like this
  name: string;
}