FilterQuery Typing fails for generic type

[david-loe]

Prerequisites

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

Mongoose version

8.2.3

Node.js version

20

MongoDB server version

7.0.6

Typescript version (if applicable)

5.4.3

Description

Repro Script throws

No overload matches this call.
  Overload 1 of 5, '(filter: FilterQuery<ModelType>, projection?: ProjectionType<ModelType> | null | undefined, options?: QueryOptions<ModelType> | null | undefined): Query<...>', gave the following error.
    Argument of type '{ _id: string | Types.ObjectId; }' is not assignable to parameter of type 'FilterQuery<ModelType>'.
      Type '{ _id: string | Types.ObjectId; }' is not assignable to type '{ [P in keyof ModelType]?: Condition<ModelType[P]> | undefined; }'.
  Overload 2 of 5, '(filter: FilterQuery<ModelType>, projection?: ProjectionType<ModelType> | null | undefined): Query<IfAny<ModelType, any, Document<...> & Require_id<...>>[], IfAny<...>, {}, ModelType, "find">', gave the following error.
    Argument of type '{ _id: string | Types.ObjectId; }' is not assignable to parameter of type 'FilterQuery<ModelType>'.
      Type '{ _id: string | Types.ObjectId; }' is not assignable to type '{ [P in keyof ModelType]?: Condition<ModelType[P]> | undefined; }'.
  Overload 3 of 5, '(filter: FilterQuery<ModelType>): Query<IfAny<ModelType, any, Document<unknown, {}, ModelType> & Require_id<ModelType>>[], IfAny<...>, {}, ModelType, "find">', gave the following error.
    Argument of type '{ _id: string | Types.ObjectId; }' is not assignable to parameter of type 'FilterQuery<ModelType>'.
      Type '{ _id: string | Types.ObjectId; }' is not assignable to type '{ [P in keyof ModelType]?: Condition<ModelType[P]> | undefined; }'.ts(2769)

Steps to Reproduce

import { Model, Types } from "mongoose";

function findById<ModelType extends {_id: Types.ObjectId | string}>(model: Model<ModelType>, _id: Types.ObjectId | string){
    return model.find({_id: _id})
}

Expected Behavior

No Error

[david-loe]

Error comes from v8.2.3.
v8.2.2 doesn't had this issue.

[david-loe]

related to #14462

[vkarpov15]

Looks like OP's script fails to compile with TypeScript 5.4.3:

$ ./node_modules/.bin/tsc --strict gh-14459.ts 
gh-14459.ts:4:23 - error TS2769: No overload matches this call.
  Overload 1 of 5, '(filter: FilterQuery<ModelType>, projection?: ProjectionType<ModelType> | null | undefined, options?: QueryOptions<ModelType> | null | undefined): Query<...>', gave the following error.
    Argument of type '{ _id: string | Types.ObjectId; }' is not assignable to parameter of type 'FilterQuery<ModelType>'.

I think this is just a limitation of TypeScript, because { _id: never } does satisfy extends {_id: Types.ObjectId | string}. For example, the following doesn't cause any errors with using { _id: never }:

import { Model, Types, model, Schema } from "mongoose";

function findById<ModelType extends {_id: Types.ObjectId | string}>(model: Model<ModelType>, _id: Types.ObjectId | string){
    return model.find({_id: _id})
}

type ModelType = { _id: never };
const TestModel = model<ModelType>('test', new Schema());

findById<ModelType>(TestModel, 'foo');

We will take a quick look to see if there's some way we can work around this weird never case

[vkarpov15]

I took a look but there's nothing we can do other than 1) make FilterQuery<T> = any, or 2) require as FilterQuery in OP's case as follows:

import { Model, Types, model, Schema, FilterQuery } from "mongoose";

function findById<ModelType extends {_id: Types.ObjectId | string}>(model: Model<ModelType>, _id: Types.ObjectId | string){
    return model.find({_id: _id} as FilterQuery<ModelType>);
}

This is suboptimal, but unfortunately a limitation of TypeScript. From this SO answer: "Never assign a concrete type to a generic type parameter, consider it as read-only!". That includes calling a function with arguments that rely on the generic type parameter.

Even if we make FilterQuery<T> = T, we get the following error '{ _id: string | Types.ObjectId; }' is assignable to the constraint of type 'ModelType', but 'ModelType' could be instantiated with a different subtype of constraint '{ _id: string | ObjectId; }'

Given that { _id: never } extends {_id: Types.ObjectId | string}, the TypeScript limitation makes sense, just quirky language design.