Type Graphql custom Resolver

Question

Iam have a User ObjectType and want in my LoginResolver, to return the user and a generated token for that user as an Object like so:

{user:User, token:string} Currently I can return either the User OR a string, depending on the Type i give in the @Mutation() decorator

@Mutation((returns) => User)
  async login(
    @Arg("email") email: string,
    @Arg("password") password: string,
    @Ctx("ctx") ctx: IContext
  ) {
    const user = await this.userRepo.findOneUser({ where: { email } });
    const success = await compare(password, user.password);
    if (!success) ctx.throw(401);
    const token = await this.tokenRepo.createToken(user);

    return user;
  }

when i try creating an UserWIthToken Objecttype I get the following Error for every field on the user entity:

app_1       |   error: [ValidationError: Cannot query field "id" on type "UserWithToken".] {
app_1       |     locations: [ [Object] ],
app_1       |     path: undefined,
app_1       |     extensions: { code: 'GRAPHQL_VALIDATION_FAILED', exception: [Object] }
app_1       |   }
app_1       | }```
dont mind the app_1 here, Iam using docker

Answer 1

You need to create a custom ObjectType for this case

@ObjectType()
class UserWithToken {
    @Field(() => User)
    user: User
      
    @Field()
    token: string
}

Then use that object in your query instead of user

@Query((returns) => UserWithToken)
async login(
    @Arg("email") email: string,
    @Arg("password") password: string,
    @Ctx("ctx") ctx: IContext
) : Promise<UserWithToken> {
    const user = await this.userRepo.findOneUser({ where: { email } });
    const success = await compare(password, user.password);
    if (!success) ctx.throw(401);
    const token = await this.tokenRepo.createToken(user);

    return {
        user,
        token
    };
}

Please note I used @Query here instead of @Mutation as it fit this case better, as a rule of thumb if you want to read data without modifying it, use Query, other wise for deleting/adding/editing data use Mutation.

Then you can run the login query like this

query {
  login(email: "xx@xx.com", password: "xxxxx") {
    token
    user {
      id
      name
      email
      ...
    }
  }
}