Pick some properties from generated Instance of type is not working, why?

Question

Trying to generate an new type with only some properties, but I'm getting nothing..

const User = types.model({
    id: types.identifier,
    username: types.maybe(types.string),
    email: types.maybe(types.string),
});
type TUser = Instance<typeof User>;
type TDatabaseUser = Pick<TUser, 'id' | 'email'>

TDatabaseUser has no properties.. and should have id and email

What I'm doing wrong ?

Answer 1

Your code seems to be working as intended.

import { Instance, types } from "mobx-state-tree";

const User = types.model({
  id: types.identifier,
  username: types.maybe(types.string),
  email: types.maybe(types.string)
});
type TUser = Instance<typeof User>;
type TDatabaseUser = Pick<TUser, "id" | "email">;

const dbUser: TDatabaseUser = {
  id: "1",
  email: "test@test.com",
  // id and email works, but username gives rise to an error.
  username: "does not work"
};