Typescript `Property is missing in type`, but the type is `never`

Question

What I want to achieve is to reference the original interface, and remove some attributes. This is my original interface:

export interface IInvitations {
    parent: Parse.User;
    visitor: Visitors;
    dates: IInvitationDateAndPin[];
}

When a user initiates the invitation, he should not give parent as a parameter. which will be auto-assigned before saving into the database. So I made a new interface to omit it:

export interface ICInvitations extends IInvitations {
    parent: never;
}

But then I cannot successfully assign value to this interface.

let data: ICInvitations = {
    visitor: Visitors,
    datas: [...]
}

It shows Property 'parent' is missing in type. But the type is never, which I failed to assign anything into it.

Answer 1

As Jeff mentioned, while you can't remove the property from the interface, you can reuse most of it by doing something like this (Omit is shipped with TypeScript 3.5):

export interface ICInvitations extends Omit<IInvitations, 'parent'> {
  parent?: never;
}

The parent?: never part is optional, but will let you get an error if anyone tries to construct something implementing this interface with a value set for parent.