Polymorphic schema on MongoDB and node.js

I didn't find any tutorials or specification on how to create a polymorphic item on mongodb.

To be clear I want to have an item with a type field, and more fields would be linked in accords to the type of the item. For example Item can be a book or a magazine. The two item have a lot in common but needs also specific fields.

So I was wondering about the best way to do it:

const itemSchema = new Schema({
  cuid: { type: 'String', required: true },
  name: { type: 'String', required: true },
  _t: { type: 'String', required: true },
  _t_id: { type: Type.ObjectId, required: true },
  category: { type: 'String', required: true },
  description: { type: 'String', required: true },
  c_at: { type: 'Date', default: Date.now, required: true },  // Created_at
  c_by: { type: 'String', default: "me", required: true },    // Created_by
  u_at: { type: 'Date', default: Date.now, required: true },  // Updtaed_at
});

Where _t is the type of item and _t_id is the id of the object. I'll then do different schemas for different type and retrieve information this way.

Is it a good solution, is there a better way ? And retrieving data might be difficult :

db.[item._t].find(item._t_id)

If you have any link or any better idea than this, I'll be glad to have your advise. Thanks for your help.

via A. K. Robert