javascript - 映射键值以使用 javascript 创建具有嵌套对象的 json 结构

Question

我想从我将从查询结果中获取的平面数组创建一个数组对象，并想创建 json 结构作为响应以将其作为 api 响应传递。例如-平面阵列-

[{
    user_id: '2311123',
    user_country: 'United States',
    user_city: 'ny',
    ssn: 229
  },
  {
    user_id: '451313',
    user_country: 'United States',
    user_city: 'abc',
    ssn: 147
  },
  {
    user_id: '65345',
    user_country: 'United States',
    user_city: 'abc',
    ssn: 444
  },
  {
     user_id: '763343',
    user_country: 'Australia',
    user_city: 'auus',
    ssn: 678
  }]

我想创建一个类似预期输出的结构

{
  "United States": [
    {
      "ny": [
        {
          "user_id": "2311123",
          "ssn": "7"
        }
      ]
    },
    {
      "abc": [
        {
          "user_id": "451313",
          "ssn": "147"
        },
        {
          "user_id": "65345",
          "ssn": "444"
        }
      ]
    }
  ],
  "Australia": [
    {
      "auus": [
        {
          "user_id": "763343",
          "ssn": "678"
        }
      ]
    }
  ]
}

其中映射了 user_country 对象数组和 user_city 对象数组。我试过这段代码，但无法达到预期的输出。:

  const map = {};
  results.forEach(arr => {
   console.log("arr",arr)
        if(map[arr.user_country]){
          if(!map[arr.user_country].includes(arr.user_city))
            map[arr.user_country].push(arr.user_city);
        }else{
          map[arr.user_country] = [arr.user_city]
        }
  });
  console.log(map);

Answer 1

这可能会产生预期的结果:

const array = [{ user_id: '2311123', user_country: 'United States', user_city: 'ny', ssn: 229 }, { user_id: '451313', user_country: 'United States', user_city: 'abc', ssn: 147 }, { user_id: '65345', user_country: 'United States', user_city: 'abc', ssn: 444 }, { user_id: '763343', user_country: 'Australia', user_city: 'auus', ssn: 678 }];


const map = array.reduce((map, {user_country, user_city, ...userInfo}) => {
  if (!map[user_country]) {
    map[user_country] = [{[user_city]: [{...userInfo}]}];
  } else {
    const ex = map[user_country].find(city => Object.keys(city)[0] === user_city);
    if (!ex) {
      map[user_country].push({[user_city]: [{...userInfo}]});
    } else {
      Object.values(ex)[0].push({...userInfo});
    }
  }
  return map;
}, {});

console.log(map);