Typescript: Mongoose lean does not return a real lean document for Array subschema

[GuiHash]

Prerequisites

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

Mongoose version

7.x

Node.js version

all

MongoDB server version

all

Typescript version (if applicable)

all

Description

Mongoose does not return a real lean document

Since v7 and the removal of LeanDocument, now when we lean a document mongoose return the raw type defined when we instantiate the schema

But when we are not providing a raw type to the schema and we let mongoose infer the type the returned type is not the good one (for instance for subSchema array)

Steps to Reproduce

import mongoose, { Schema } from "mongoose";

const subSchema = new Schema({ name: String });

const schema = new Schema({
  sub: { type: [subSchema] },
});

const Model = mongoose.model("Model", schema);

const c = await Model.findById("my-id").lean();

c;
// ^? const c: (mongoose.FlattenMaps<{ sub: mongoose.Types.DocumentArray<{ name?: string | undefined }> }> & { _id: mongoose.Types.ObjectId }) | null;

The return type for the subSchema is mongoose.Types.DocumentArray

Typescript playground example

Expected Behavior

import mongoose, { Schema } from "mongoose";

const subSchema = new Schema({ name: String });

const schema = new Schema({
  sub: { type: [subSchema] },
});

const Model = mongoose.model("Model", schema);

const c = await Model.findById("my-id").lean();

c;
// ^? const c: (mongoose.FlattenMaps<{ sub: Array<{ name?: string | undefined }> }> & { _id: mongoose.Types.ObjectId }) | null;

The return type for the subSchema is Array

[GuiHash]

Sorry after more research it is a duplicate of #13772