problem description

< H2 > how does mongoose jointly check and complete the data and then classify and aggregate according to the fields of the joint search? < / H2 >

I now have two tables: a product table Product , a product category table Category , a product table option associated category table,

Product Table

const mongoose  =  require("../index")
const  Schema = mongoose.Schema;
const ObjectId = Schema.Types.ObjectId
const newSchema = new Schema({
  name:String,
  dec:String,
  tags:Array,
  originalPrice:Number,
  presentPrice:Number,
  proImg:Array,
  detailImg:Array,
  option:{
    type:ObjectId,
    ref:"Category"
  },
})
module.exports = mongoose.model("Product",newSchema,"product")

Category Table

const mongoose  =  require("../index")
const  Schema = mongoose.Schema;
const newSchema = new Schema({
  name:String,
  isShow:{
    type:Boolean,
    default:true,
    },
})
module.exports = mongoose.model("Category",newSchema,"category")

General joint search const data = await dbProduct.find (). Populate ("option")

router.get("/homeLists/index", async ctx => {
  // 201871517:38:12  
  // const lists = await dbProduct.aggregate().group({_id:"$option"}).count("productNumber")
  // console.log("lists :", lists);
  const categoryLists = await dbCategory.find()
  const productLists = await dbProduct.find()
  let tempList = []
  categoryLists.forEach(cItem => { //
    let categoryInfo = {
      title: cItem.name,
      subTitle: "Fashion Make-up", // 
      list: []
    }
    productLists.forEach(pItem => {
      if (pItem.option.toString() == cItem._id.toString()) { //_id  _id  
        console.log("true :", true);
        let productInfo = {
          productName: pItem.name,
          proDec: pItem.dec,
          img: pItem.proImg[0]
        }
        categoryInfo.list.push(productInfo)
      }
    });
    tempList.push(categoryInfo) //
  })

  ctx.body = tempList
})

I hope to use the aggregation function of mongoose to achieve it at one time!