Make objection model return match the TS interface

Question

I'm working to implement an api using express/objection js and typescript.

I took a lot of inspiration from this repo: https://github.com/HappyZombies/brackette-alpha/tree/master/server/src

As the creator did, I want to have different interfaces for a same "component" ( eg: user ).

We can see here that he create different interfaces (here) and he uses them in his services as a returned promise (here) but there is no check that what he returned does match his interface. Eg: to match his promised interface here, he will only select the sql field that match his interface

  public async findAll(): Promise<IUserMiminimum[]> {
    let users;
    try {
      users = await this.usersModel.query().column('username', 'displayName');
    } catch (err) {
      this.logger.error(err);
      throw err;
    }
    return users;
  }

My questions are:

• Is there a way to only select the fields you want from the model results based on the interface description ?
• Else, is there a way to check the interface match the model results ?

Thanks for reading.

Answer 1

Objection castTo() might help with that

const users= await User.query()
  .column('username', 'displayName')
  .castTo<IUser[]>();