Below is the create-user-dto file where I have used to create the creation of an account including a username, password and a role. Done using arrays. Although I have set it up still it shows’ white space in my array.

import { Transform } from "class-transformer";
import { IsString, MinLength, MaxLength, Matches, IsIn } from "class-validator";

export class CreateUserDto{
    @IsString()
    @MinLength(4)
    @MaxLength(20)
    @Transform(({ value }) => value.trim())
    username: string;
  
    @IsString()
    @MinLength(8)
    @MaxLength(20,{
      message: 'Password can contain only 20 characters',
    })
    @Matches(/(?:(?=.*d)(?=.*[a-z])(?=.*[A-Z]).*)/, {
      message: 'Password too weak',
    })
    @Transform(({ value }) => value.trim())
    password: string;
  
    
    @IsString()
    @IsIn(['Teacher', 'Admin'], {
      message: 'Role must be either Teacher or Admin'
    })
    @Transform(({ value }) => value.trim())
    role: 'Teacher' | 'Admin';
}

Controller class code: –

@Post('register')
    @UsePipes(new ValidationPipe({transform:true, whitelist: true}))
    async createUser(@Body() createUserDto: CreateUserDto): Promise<string> { 
        const existingUser = this.userService.findUser(createUserDto.username);
        if(existingUser){
            throw new BadRequestException("Username already exists");
        }

        this.userService.createUser(createUserDto.username, createUserDto.password, createUserDto.role);
        return 'User created successfully';
    }

Once I save the password with spaces it should save without the spaces right. Still the array has saved the password with an empty space.