如何按字段值多次对对象数组进行分组？

Question

我有一个从 API 响应中获得的对象数组，并且希望对其进行格式化，以便它可以用于具有嵌套项目的菜单。

[
    {
        "id": 1,
        "name": "The Cool Association",
        "description": "the office",
        "country": "United Kingdom",
        "county": "North Lanarkshire",
        "town": "Airdrie",
        "address": "test addr 1",
        "postcode": null,
        "latlong": {
            "x": -3.97369,
            "y": 55.8665
        },
        "mainCategory": Hills,
        "subCategory": 17,
        "refCode": "airdrie"
    },
    {
        "id": 2,
        "name": "Test Locations",
        "description": "testing",
        "country": "United Kingdom",
        "county": "Aberdeenshire",
        "town": "Airdrie",
        "address": "test addr 1",
        "postcode": null,
        "latlong": {
            "x": -4.02652,
            "y": 55.8611
        },
        "mainCategory": Mountains,
        "subCategory": null,
        "refCode": "coat"
    },
    {
        "id": 3,
        "name": "Test Locations",
        "description": "testing",
        "country": "Scotland",
        "county": "North Lanarkshire",
        "town": "Airdrie",
        "address": "test addr 1",
        "postcode": null,
        "latlong": {
            "x": -4.02652,
            "y": 55.8611
        },
        "mainCategory": Main Category,
        "subCategory": null,
        "refCode": "test"
    },
    {
        "id": 4,
        "name": "NL Leisure",
        "description": "leisure",
        "country": "United Kingdom",
        "county": "North Lanarkshire",
        "town": "Airdrie",
        "address": "test addr 1",
        "postcode": null,
        "latlong": {
            "x": -4.02652,
            "y": 55.8611
        },
        "mainCategory": Sports,
        "subCategory": null,
        "refCode": "hello"
    }
]

我希望首先按国家/地区对响应进行分组，然后按县对国家内的响应进行分组，然后按主要类别对县内的响应进行分组。这可能吗？

[
   "Scotland":{
      "North Lanarkshire":{
         "MainCategory":{
            "...details"
         }
      }
   },
   "UnitedKingdom":{
      "North Lanarkshire":{
         "Hills":{
            "...details"
         },
         "Sports":{
            "...details"
         }
      },
      "Aberdeenshire":{
         "Mountains":{
            "...details"
         }
      }
   }
]

我尝试了各种reduce方式并使用lodash提供的_.groupBy函数，但未能最终得到我正在寻找的格式。在 API 级别对其进行格式化会更好吗？任何帮助表示赞赏

Answer 1

const arr = [{
    "id": 1,
    "name": "The Cool Association",
    "description": "the office",
    "country": "United Kingdom",
    "county": "North Lanarkshire",
    "town": "Airdrie",
    "address": "test addr 1",
    "postcode": null,
    "latlong": {
      "x": -3.97369,
      "y": 55.8665
    },
    "mainCategory": 'Hills',
    "subCategory": 17,
    "refCode": "airdrie"
  },
  {
    "id": 2,
    "name": "Test Locations",
    "description": "testing",
    "country": "United Kingdom",
    "county": "Aberdeenshire",
    "town": "Airdrie",
    "address": "test addr 1",
    "postcode": null,
    "latlong": {
      "x": -4.02652,
      "y": 55.8611
    },
    "mainCategory": 'Mountains',
    "subCategory": null,
    "refCode": "coat"
  },
  {
    "id": 3,
    "name": "Test Locations",
    "description": "testing",
    "country": "Scotland",
    "county": "North Lanarkshire",
    "town": "Airdrie",
    "address": "test addr 1",
    "postcode": null,
    "latlong": {
      "x": -4.02652,
      "y": 55.8611
    },
    "mainCategory": 'Main Category',
    "subCategory": null,
    "refCode": "test"
  },
  {
    "id": 4,
    "name": "NL Leisure",
    "description": "leisure",
    "country": "United Kingdom",
    "county": "North Lanarkshire",
    "town": "Airdrie",
    "address": "test addr 1",
    "postcode": null,
    "latlong": {
      "x": -4.02652,
      "y": 55.8611
    },
    "mainCategory": 'Sports',
    "subCategory": null,
    "refCode": "hello"
  }
]
const result = arr.reduce((acc, curr) => {
  const country = acc[curr.country] || {};
  const county = country[curr.county] || {};
  const mainCategory = county[curr.mainCategory] || {};
  mainCategory[curr.name] = curr;
  county[curr.mainCategory] = mainCategory;
  country[curr.county] = county;
  acc[curr.country] = country;
  return acc;
}, {});
console.log(JSON.stringify(result, null, 2));