title: TypeORM Polymorphic Relations
body: <p>I am migrating a Laravel app to Node app using TypeORM. Has anyone been able to implement something similar to <a href="https://laravel.com/docs/5.6/eloquent-relationships#polymorphic-relations" rel="noreferrer">Laravel's Polymorphic Relations</a> in TypeOrm?</p>
  
  <p>Example schema I am trying to reproduce:</p>
  
  <pre><code>export class Notification {
      id: string;
      attachable_id: number;
      attachable_type: string;
  }
  </code></pre>
  
  <p>I want to be able to to have a notification.attachable relation that could be of any type. Then, ideally, I can eager load a user with their last x notifications, with the attachable on each notification.</p>