dontDoThis.ts

// graphql.ts

// ...other codes

const loaders = () => {
  return {
    // ...other loaders
    getProductsByMerchantId(pagination: IPagination){
      const {limit, offset, orderBy, sortBy, search} = pagination;
      return new Dataloader(async merchantIds => {
        const connection = Knex(config.get('database'));
        const table = connection('products');
        const {limit, offset, orderBy, sortBy, search} = productsPagination;
        
        if(search)
          table.where('name', 'LIKE', `%${search}%`);
        
        const products = await connection.union(
            merchantIds.map(id =>
                table
                    .where('merchantId', id)
                    .orderBy(orderBy, sortBy)
                    .limit(limit)
                    .offset(offset)
            ),
            true //option for wrap queries
        );
        return merchantIds.map(merchantId => products.filter(product => product.merchantId === merchantId));
      });
    }
  };
};

// ...other codes