How to get Nested data in node js

Here is the code i write for getting above array result in nodejs

pool.query(`Select * FROM categories WHERE catalog_id = '${fields.catalog_id}'`, async (error, result, field) => {
  if (error) { // if error 
    console.log(error);
    return false; 
  }
    
    var Catarr = result.map((item,index)=>item.id)
    pool.query(`Select * FROM items WHERE category_id IN (${Catarr})`, async (error, menuItems, field) => {
      if (error) { // if error 
        console.log(error);
        return false; 
      }
      var parsed_items = [];

       await result.forEach((item,index)=>{
          var items = menuItems.filter((p_item)=>p_item.category_id == item.id)
            var obj = {
              name: item.name,
              id: item.id,
              items
            }
            parsed_items.push(obj)
        })
      
        res.status(200).json({status:true,total_results:result.length,categories:parsed_items});
    });
  });

Sharing my suggestion as per my understanding; Please refer to below code snippet:

const data={    "status": true,
    "total_results": 4,
    "categories": [
        {
            "id": 2,
            "name": "Category 1",
            "items":[
                 {
                    "name" :"item1"
                 },
                 {
                    "name": "item2"
                 }
             ]
        },
        {
            "id": 4,
            "name": "Category 2",
             "items":[
                 {
                    "name" :"item1"
                 },
                 {
                    "name": "item2"
                 }
             ]
        }
    ]
};

const expectedResult=data.categories.reduce((iter, item)=>{

  iter[item.name]=item.items? item.items.length : 0; // we can use item.id if required
  return iter;

}, {});

alert(JSON.stringify(expectedResult));
console.log('Items per category - ',expectedResult);