feat: add `@IsMongoIdObject` decorator

Description

1. @IsMongoId() just checks if it is a string (see below, taken from your code base) where you could have used ObjectId.isValid() from the mongodb or bson repo.
2. Is this repo still maintained?

export function isMongoId(value: unknown): boolean {
    return typeof value === "string" && validator.isMongoId(value);
}

Reproduction

Create a Mongo Id with new ObjectId() and you’ll get an error when validating. Can’t provide any sandbox. Tried Stackblitz and CodeSandbox but they can’t get bson or mongodb running. So you have try yourself in you IDE:

import { IsMongoId, validateSync } from 'class-validator'
import { ObjectId } from 'mongodb'

class A {
  @IsMongoId()
  _id = new ObjectId()
}

console.log(validateSync(new A()))

Environment

• nodejs: 14.4
• browser: not relevant
• framework/library: nothing

class-validator version: 0.12.2

[Kiliandeca]

Hello, I think this is the intended behaviour, most of the decorator are under the “String validation decorators” section in the readme.

Internally this library use validator.js to perform validation and as you can see it’s “A library of string validators and sanitizers”.

It’s wrong to say that it just checks if it is a string because as you can see from the code you quote we also do the validator.js check. && validator.isMongoId(value);. You can find the underlying code at this url. It check if it’s an hexadecimal string of lenght 24. If this is not the right behavior you can open an issue upstream but using mongodb or bson to do object validation seem out of scope since it’s a string validation library.

However you can probably do what you want with class-validator using custom validation decorator (link to the doc)

I did not test but It would look something along the line of:

import {registerDecorator, ValidationOptions, ValidationArguments} from "class-validator";
import { ObjectId } from "bson"

export function IsMongoIdObject(validationOptions?: ValidationOptions) {
   return function (object: Object, propertyName: string) {
        registerDecorator({
            name: "IsMongoIdObject",
            target: object.constructor,
            propertyName: propertyName,
            constraints: [],
            options: validationOptions,
            validator: {
                validate(value: any, args: ValidationArguments) {
                    return ObjectId.isValid(value)
                }
            }
        });
   };
}

then use it as:

class A {
  @IsMongoIdObject()
  _id = new ObjectId()
}

[desmap]

Thanks. I saw that I can create a custom validator, so this should do the job for now.

I think this is the intended behaviour, most of the decorator are under the “String validation decorators” section in the readme.

IDK, following your logic (it’s in a ‘string’ subfolder + the upstream repo isn’t doing more) you might be right. But from a user’s view who just ESM-imports { IsMongoId } without reading the sources or folder structures too much, he/she assumes and expects it’s the original validator function from the bson lib. So, this might be intended from your side but it’s still misleading.