class-transformer does not work : Transform function is not called

Question

I try to use class-transformer but i can't do it. I also use type-graphql and @typegoose/typegoose Here's my code:

My Decorator

import { Transform } from 'class-transformer';

export function Trim() {
  console.log('DECORATOR');

  return Transform(({ value }: { value: string }) => {
    console.log('value: ', value);
    return value.trim();
  });
}

My InputType

import { IsEmail } from 'class-validator';
import { InputType, Field } from 'type-graphql';
import { User } from '../Entities/User';
import { Trim } from '../../Decorators/Sanitize';

@InputType({ description: 'Input for user creation' })
export class AddUserInput implements Partial<User> {
  @Field()
  @Trim()
  @IsEmail({ domain_specific_validation: true, allow_utf8_local_part: false })
  email!: string;
}

My Resolver

import { Arg, Mutation, Resolver } from 'type-graphql';
import { User } from '../Entities/User';
import { AddUserInput } from '../Types/UsersInputs';

@Resolver(() => User)
export class UserResolvers {
  @Mutation(() => String, { description: 'Register an admin' })
  async createAccount(@Arg('data') data: AddUserInput): Promise<string> {
    console.log({ ...data });
    return data.email;
  }
}

My Entity

import { prop, getModelForClass } from '@typegoose/typegoose';
import { ObjectType, Field } from 'type-graphql';

@ObjectType({ description: 'User model' })
export class User {
  @Field({ description: 'The user email' })
  @prop({ required: true, unique: true, match: [/\S+@\S+\.\S+/, 'is invalid'] })
  email!: string;
}

export const UserModel = getModelForClass(User, {
  schemaOptions: { timestamps: true }
});

My Request

POST http://localhost:5000/app HTTP/1.1
Content-Type: application/json
X-REQUEST-TYPE: GraphQL

mutation 
{
   createAccount (data : {
       email: "   email@gmail.com    ",
   })
}

The problem is that the console.log('value: ', value) inside Transform function is never call and my email is not trim.

Also console.log('DECORATOR') is not call when I do the request but just one time when server starting.

Thanks !

Answer 1

Typegoose transpiles classes into mongoose schemas & models, it does not apply any validation / transformation aside from mongoose provided ones, so your class-transformer decorators would only be called when using the class directly and using its functions. (like plainToClass and classToPlain )

In your case, it would be better to either use PropOptions get & set or pre-hooks .

As a note, typegoose provides a guide for using class-transformer with typegoose classes Integration Example: class-transformer , just to show that it can be used like normal classes.

Also note, it is currently recommended against using class-transformer because of mentioned issues inside the documentation.