classTransformer @Transfrom fails when instance of Decimal passes as a value.

[OleksandrKostrov]

Packages versions: "@prisma/client": "5.11.0", "class-transformer": "0.5.1"

I am trying to serialize my API response with @Transform() decorator from 'class-transformer' library. I am getting object from db using PrismaService, initialized with

`import { Injectable, OnModuleInit } from '@nestjs/common';
import { PrismaClient } from '@prisma/client';

@Injectable()
export class PrismaService extends PrismaClient implements OnModuleInit {
async onModuleInit() {
await this.$connect();
}
}`

I have class for API response serialization:

@exclude()
export class MyResponse {
@Transform(({ value }) => value.toNumber())
@expose()
age: number;
}

age field is instance of Decimal from Decimal.js.

Expected behavior: Decimal to converts to number after value.toNumber() in @Transform() decorator callback.

Current behavior: [Nest] 20138 - 04/17/2024, 12:06:08 PM ERROR [ExceptionsHandler] [DecimalError] Invalid argument: undefined
Error: [DecimalError] Invalid argument: undefined
at new i (/Users/mypc/projects/someproject/my-project/node_modules/.pnpm/@prisma+client@5.11.0_prisma@5.11.0/node_modules/@prisma/client/runtime/library.js:23:29389)
Code execution is not even get into Transform decorator callback.