Using method 1 may save a small amount of time by not having to redefine DTO type definitions for service methods, but ultimately it is not worth the trade-off. It is recommended to use method 2 instead.
As your application grows, there may be instances where service methods are called from other services or controllers. This can lead to situations where callers of a service must provide unnecessary extra parameters in order to call the method.
For example, consider a scenario where you have a UsersService and UsersController for handling user registration:
class UsersController() {
@Post('register')
register(@Body() dto: RegisterUserDto) {
const isVerified = this.verificationService.verify(dto.code);
if (isVerified) {
return this.usersService.create(dto);
}
}
}
class UsersService() {
create(dto: RegisterUserDto) {
// create user...
}
}
Everything works fine until a few months later when a client requests the ability to manually add users from their dashboard. Even though you already have an implemented create method in UsersService, you cannot directly use it in
AdminController</code because the method requires a <code>code
parameter. The compiler will not allow you to call the method without providing the required parameter, even if it is not actually used in the
create method.