my typegoose save function didn't return needed type (NodeJs, typescript, graphql)

Question

My function save of an object (in model.ts file) which is created by typegoose should return Promise<Todo> but it returns Promise<Document<any, {}>> and i have this error :

Type 'Document<any, {}>' is missing the following properties from type 'Todo': createdAt, updatedAt, content, isDone

How should i correct this ?

model ts

import { getModelForClass } from "@typegoose/typegoose";
import { ObjectId } from "mongodb";

import { Todo } from "../../entities";
import { NewTodoInput } from "./input";

// This generates the mongoose model for us
export const TodoMongooseModel = getModelForClass(Todo);

export default class TodoModel {
  async getById(_id: ObjectId): Promise<Todo | null> {
    // Use mongoose as usual
    return TodoMongooseModel.findById(_id).lean().exec();
  }

  async create(data: NewTodoInput): Promise<Todo> {
    const todo = new TodoMongooseModel(data);

    return todo.save();
  }
}

input ts

import { Field, InputType, ID } from "type-graphql";
import { MaxLength, MinLength } from "class-validator";

@InputType()
export class NewTodoInput {
  @Field()
  @MaxLength(300)
  @MinLength(1)
  content: string | undefined;

}

entities todo ts

import { ObjectType, Field } from "type-graphql";
import { prop } from "@typegoose/typegoose";
import { ObjectId } from "mongodb";

@ObjectType()
export class Todo {
  @Field()
  readonly _id!: ObjectId;

  @prop()
  @Field(() => Date)
  createdAt!: Date;

  @prop()
  @Field(() => Date)
  updatedAt!: Date;

  @prop()
  @Field()
  content!: string;

  @prop({ default: false })
  @Field()
  isDone!: boolean;
}

Thank you.

Answer 1

with the unofficial mongoose types, it is an known problem that await document.save() does not return the correct typings
-> this is not an problem with typegoose, it is with @types/mongoose

the workaround is to use:

await doc.save();
return doc;

(or maybe in your case directly use the mongoose provided function .create)

PS: this is not a problem in the official types of mongoose (can be currently used with typegoose 8.0.0-beta.x)