types(DocumentArray): pass DocType generic to Document for correct toJSON() and toObject() return types

Fix #14469

Author: vkarpov15

test/types/docArray.test.ts

@@ -1,4 +1,4 @@
-import { Schema, model, Types, InferSchemaType } from 'mongoose';
+import { Schema, model, Model, Types, InferSchemaType } from 'mongoose';
 import { expectError, expectType } from 'tsd';
 
 async function gh10293() {
@@ -127,3 +127,38 @@ async function gh14367() {
   expectType<boolean | null | undefined>({} as IUser['reminders'][0]['toggle']);
   expectType<string | null | undefined>({} as IUser['avatar']);
 }
+
+function gh14469() {
+  interface Names {
+    _id: Types.ObjectId;
+    firstName: string;
+  }
+  // Document definition
+  interface User {
+    names: Names[];
+  }
+
+  // TMethodsAndOverrides
+  type UserDocumentProps = {
+    names: Types.DocumentArray<Names>;
+  };
+  type UserModelType = Model<User, {}, UserDocumentProps>;
+
+  const userSchema = new Schema<User, UserModelType>(
+    {
+      names: [new Schema<Names>({ firstName: String })]
+    },
+    { timestamps: true }
+  );
+
+  // Create model
+  const UserModel = model<User, UserModelType>('User', userSchema);
+
+  const doc = new UserModel({ names: [{ firstName: 'John' }] });
+
+  const jsonDoc = doc?.toJSON();
+  expectType<string>(jsonDoc?.names[0]?.firstName);
+
+  const jsonNames = doc?.names[0]?.toJSON();
+  expectType<string>(jsonNames?.firstName);
+}

types/types.d.ts

@@ -60,7 +60,7 @@ declare module 'mongoose' {
 
     class Decimal128 extends mongodb.Decimal128 { }
 
-    class DocumentArray<T> extends Types.Array<T extends Types.Subdocument ? T : Types.Subdocument<InferId<T>> & T> {
+    class DocumentArray<T> extends Types.Array<T extends Types.Subdocument ? T : Types.Subdocument<InferId<T>, any, T> & T> {
       /** DocumentArray constructor */
       constructor(values: AnyObject[]);
 
@@ -83,7 +83,7 @@ declare module 'mongoose' {
     class ObjectId extends mongodb.ObjectId {
     }
 
-    class Subdocument<IdType = any> extends Document<IdType> {
+    class Subdocument<IdType = any, TQueryHelpers = any, DocType = any> extends Document<IdType, TQueryHelpers, DocType> {
       $isSingleNested: true;
 
       /** Returns the top level document of this sub-document. */