Mongoose paginate typescript

paginate.ts

/** @see https://discord.com/channels/612400042900193311/612406252164612129/869681421567000608 **/
export async function queryPaginate<T>(
    model: ModelType<T>,
    pageNum = 1,
    filter: MongooseFilterQuery<DocumentType<T>>,
    populate?: string[],
): Promise<IPaginatedData<T[]>> {
    const [docs, total] = await Promise.all([
        model
            .find(filter)
            .sort({ createdAt: -1 })
            .limit(20)
            .skip(pageNum === 1 ? 0 : (pageNum - 1) * 20)
            .populate(populate)
            .exec(),
        model.countDocuments(filter).exec(),
    ]);
    const totalPages = total > 0 ? Math.ceil(total / 20) || 1 : 0;
    const nextPage = pageNum < totalPages ? pageNum + 1 : null;
    return {
        items: docs.map((e) => e.toJSON() as T),
        total,
        totalPages,
        nextPage,
        pageNumber: pageNum,
    };
}