DeepModelObject for Model classes that also have Model properties

[yayza]

I'm using ModelObject to create pojos version of my models so I can use them throughout my app. One thing I noticed is if a model has props that are also Models, the ModelObject type keeps them as Model types. instead of transforming them into ModelObjects too.

I created a DeepModelObject type that recursively checks for nested Models and transforms them into ModelObjects.

import { Model, type DataPropertyNames } from "objection";

declare global {
    type DeepModelObject<T extends Model> = Pick<
        {
            [P in keyof T]: T[P] extends Model
                ? DeepModelObject<T[P]>
                : T[P] extends Model | undefined
                ? DeepModelObject<Exclude<T[P], undefined>> | undefined
                : T[P] extends Array<infer U> | undefined
                ? U extends Model
                    ? DeepModelObject<U>[]
                    : U[]
                : T[P];
        },
        DataPropertyNames<T>
    >;
}

export {};

export class DbProduct extends BaseModel {
    static tableName: string = "product";
    static virtualAttributes: string[] = [...super.virtualAttributes, ];

    // Columns
    name?: string;
    brand: string;
    category_id: number;
    manufacturer_id: number;
    description: string;
    is_active: boolean;
    slug: string;

    //Relations:
    category: DbCategory;
    manufacturer: DbManufacturer;
    attributes?: (DbAttribute & ProductAttribute)[];
    variants?: DbProductVariant[];

   //... relationMappings , etc.
}

If I use
export type Product = DeepModelObject<DbProduct>

type Product = {
    name?: string;
    brand: string;
    category_id: number;
    manufacturer_id: number;
    description: string;
    is_active: boolean;
    slug: string;
    category: DeepModelObject<DbCategory>;
    manufacturer: DeepModelObject<DbManufacturer>;
    attributes?: DeepModelObject<DbAttribute & ProductAttribute>[];
    variants?: DeepModelObject<DbProductVariant>[];
    ...
    ...
    ...
}

Nested models of models will be transformed also. I'm pretty new to TS so this took me a lot longer to figure out than I'd like to admit 😅, but thought I'd post here in case someone needs this.