嵌套层次上的猫鼬分类

Question

大家好，我是节点js社区的新手。

我正面临一个问题，与第二级过滤的类别。请帮助我如何过滤二级分组。

我的原始数据如下所示

Clothing
    Shoe    
        PUMA
Clothing
    Shoe    
        NIKE
Clothing
    Watches 
        TIMEX
Electronics
    Laptop
        DELL
Electronics
    Monitor
        HP

我在寻找像这样的

Clothing
    Shoe    
        PUMA    
        NIKE
    Watches 
        TIMEX
        
Electronics
    Laptop
        DELL
    Monitor
        HP

我的JSON如下所示，如何分组才能得到上述结果

{
    "success": true,
    "data": [
        {
            "_id": "618a094d36143c2c807f0124",
            "parentId": null,
            "title": "Clothing",
            "level2": {
                "_id": "618a098636143c2c807f0129",
                "parentId": "618a094d36143c2c807f0124",
                "title": "Shoe",
                "level3": {
                    "_id": "618a09ba36143c2c807f012e",
                    "parentId": "618a098636143c2c807f0129",
                    "title": "PUMA"
                }
            }
        },
        {
            "_id": "618a094d36143c2c807f0124",
            "parentId": null,
            "title": "Clothing",
            "level2": {
                "_id": "618a098636143c2c807f0129",
                "parentId": "618a094d36143c2c807f0124",
                "title": "Shoe",
                "level3": {
                    "_id": "618b820ebd59b4c554d880f3",
                    "parentId": "618a098636143c2c807f0129",
                    "title": "NIKE"
                }
            }
        },
        {
            "_id": "618a094d36143c2c807f0124",
            "parentId": null,
            "title": "Clothing",
            "level2": {
                "_id": "618a099136143c2c807f012b",
                "parentId": "618a094d36143c2c807f0124",
                "title": "Watches",
                "level3": {
                    "_id": "618a09d436143c2c807f0130",
                    "parentId": "618a099136143c2c807f012b",
                    "title": "TIMEX"
                }
            }
        },
        {
            "_id": "618a095f36143c2c807f0126",
            "parentId": null,
            "title": "Electronics",
            "level2": {
                "_id": "618a09ed36143c2c807f0132",
                "parentId": "618a095f36143c2c807f0126",
                "title": "Laptop",
                "level3": {
                    "_id": "618a0a0336143c2c807f0134",
                    "parentId": "618a09ed36143c2c807f0132",
                    "title": "Dell"
                }
            }
        },
        {
            "_id": "618a095f36143c2c807f0126",
            "parentId": null,
            "title": "Electronics",
            "level2": {
                "_id": "618a0a2136143c2c807f0136",
                "parentId": "618a095f36143c2c807f0126",
                "title": "Monitor",
                "level3": {
                    "_id": "618a0a2e36143c2c807f0138",
                    "parentId": "618a0a2136143c2c807f0136",
                    "title": "HP"
                }
            }
        }
    ]
}

Answer 1

你可以这样做：

Collection
  .find({},"collectionName"))
   .populate({
      path: "categories",
      model:"Category",
      select:"categoryName subCategories",
      populate:{
        path:"products",
        model:"Product",
      }
   }).then((products)=>{
    res.status(200).json(products);
   });
}