Would FieldResolver overfetch when the field was already populated?

[Tokenyet]

Just a curious about how does FieldResolver work, here is the use case for the question.

  @Authorized([AccountPermission.Business.toString()])
  @Mutation(() => Mobile)
  async mobileCreate(@Ctx() ctx: Context, @Arg('mobile') mobileInput: CreateMobileInput): Promise<Mobile> {
    const doc= await BusinessModel.findById(new ObjectId(ctx.payload.id)).exec();
    const mobileDoc = new MobileModel();

    doc.driver = businessDoc;
    doc.title = mobileInput.title;
    doc.contact = mobileInput.contact;

    try {
      await doc.save();
    } catch(err) {
      throw new InternalServerError();
    }
    
    return doc;
  }

Because I created a Mobile and pass a real doc on driver field, so It's enough for returning the data and no need MobileResolver to call @FieldResolver on driver field. In my little experience, @FieldResolver would still be called to do the job, again, right? Just asking If It's normal to do this on object creation.

[MichalLytek]

Yes, FieldResolver overwrites the default object[property] field resolver.

If you can have the value populated in some cases, you can just add if (value) return value statement in the field resolver.

[Tokenyet]

Thanks for the prompt reply 😆.