file.ts

interface InternalEventBrand {
  readonly Internal: unique symbol;
}

type User = {}

type AuthorizedEvent = { type: 'AUTHORIZED'; user: User } & InternalEventBrand;

function authorized(user: User): AuthorizedEvent {
  return { type: 'AUTHORIZED', user } as AuthorizedEvent;
}

type UnauthorizedEvent = { type: 'UNAUTHORIZED' } & InternalEventBrand;

function unauthorized(): UnauthorizedEvent {
  return { type: 'UNAUTHORIZED' } as UnauthorizedEvent;
}

export type AuthEvent =
  | { type: 'AUTHORIZATION' }
  | AuthorizedEvent
  | UnauthorizedEvent
  | { type: 'SIGN_IN' }
  | { type: 'SIGN_OUT' };