Branding and DTOs in typescript

dummy.ts

declare const ___brand: unique symbol;

type Branded<A, B> = A & { readonly [___brand]: B };

type UID = Branded<number, User>;

interface User {
  id: UID;
  name: string;
  lastLogin: Date;
  items: {
    name: string;
    creationDate: Date;
  }[],
  alias: string[]
}

type DtoBaseTypes = number|string|boolean|number[]|string[]|boolean[];

type Dto<T> = {
  [P in keyof T]: T[P] extends Date ? string : T[P] extends DtoBaseTypes ? T[P] : Dto<T[P]>
};

function userFromDto(dto: Dto<User>): User {
  return {
    ...dto,
    lastLogin: new Date(dto.lastLogin),
    items: dto.items.map(item => ({
      ...item,
      creationDate: new Date(item.creationDate)
    }))
  }
}

const user = userFromDto({
  id: 123 as UID,
  name: 'Alice',
  lastLogin: '2021-05-07T09:49:06.888Z',
  items: [{
    name: 'A',
    creationDate: '2021-05-07T09:49:06.888Z'
  }],
  alias: ['hello', 'world']
});