Using typeKey and required throws a TypeError: Invalid schema configuration

[greenafrican]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

8.6.3

Node.js version

20.x

MongoDB server version

6.0.16

Typescript version (if applicable)

5.5.1

Description

When defining a model like:

const SightingSchema = new Schema(
  {
    _id: { $type: Schema.Types.ObjectId, required: true },
    ...,
    location: {
      type: { $type: String, required: true },
      coordinates: [{ $type: Number }],
    },
  },
  {
    typeKey: "$type",
  }
);

I get the error:

TypeError: Invalid schema configuration: `true` is not a valid type at path `required`. See https://bit.ly/mongoose-schematypes for a list of valid schema types.

      3 |
    > 4 | const SightingSchema = new Schema(
        |                        ^
      5 |   {
      6 |     _id: { $type: Schema.Types.ObjectId, required: true }

      at Schema.add (node_modules/mongoose/lib/schema.js:740:13)
      at Schema.add (node_modules/mongoose/lib/schema.js:778:12)
      at new Schema (node_modules/mongoose/lib/schema.js:143:10)
      ...

When I don't use the typeKey: $type and just use type it works but can't be right for GeoJSON and as recommended in the Mongoose docs - https://mongoosejs.com/docs/guide.html#typeKey) and I get a warning in my tests:

Property 'coordinates' does not exist on type '{ type?: string | null | undefined; required?: unknown; }'

Steps to Reproduce

1. use typeKey: $type in the options
2. use required: true for the field

Expected Behavior

I expect it work just as it does without using a custom typeKey.

[vkarpov15]

I'm unable to repro, the following script runs successfully:

import mongoose from 'mongoose';

const { Schema } = mongoose;

const SightingSchema = new Schema(
  {
    _id: { $type: Schema.Types.ObjectId, required: true },
    location: {
      type: { $type: String, required: true },
      coordinates: [{ $type: Number }],
    },
  },
  {
    typeKey: "$type",
  }
);

Are you sure you don't have somewhere in your schema where you're using type instead of $type? For example, the following script prints the exact error message you're seeing, notice that test uses type instead of $type.

const SightingSchema = new Schema(
  {
    _id: { $type: Schema.Types.ObjectId, required: true },
    location: {
      type: { $type: String, required: true },
      coordinates: [{ $type: Number }],
    },
    test: { type: String, required: true }
  },
  {
    typeKey: "$type",
  }
);

We're investigating a workaround for the Property 'coordinates' does not exist on type '{ type?: string | null | undefined; required?: unknown; }' issue that doesn't involve using typeKey.