从 JavaScript 中的对象数组创建嵌套对象 [关闭]

Posted 2023-02-22

【中文标题】从 JavaScript 中的对象数组创建嵌套对象 [关闭]

【英文标题】：Create nested object from array of objects in JavaScript [closed]

【发布时间】：2019-09-23 19:11:06

【问题描述】：

我有一组对象数据：

[
  "company": "Google", "country": "USA", "employee": "John",
  "company": "Amazon", "country": "UK", "employee": "Arya",
  "company": "Google", "country": "KSA", "employee": "Cersi",
  "company": "Amazon", "country": "USA", "employee": "Tyrion",
  "company": "Amazon", "country": "USA", "employee": "Daenarys",
  "company": "Google", "country": "KSA", "employee": "Dothrokhi"
]

如何创建如下所示的嵌套对象？

  "Amazon": 
    "UK": "Arya": null, 
    "USA": "Tyrion": null, "Daenarys": null
  ,
  "Google": 
    "KSA": "Cersi": null, "Dothrokhi": null,
    "USA": "John": null
  

【参考方案1】：

您可以使用reduce 循环遍历数组并将其汇总为一个对象。

let arr = ["company":"Google","country":"USA","employee":"John","company":"Amazon","country":"UK","employee":"Arya","company":"Google","country":"KSA","employee":"Cersi","company":"Amazon","country":"USA","employee":"Tyrion","company":"Amazon","country":"USA","employee":"Daenarys","company":"Google","country":"KSA","employee":"Dothrokhi"]

let result = arr.reduce((c, v) => 
  c[v.company] = c[v.company] || ;                         //Init if company property does not exist
  c[v.company][v.country] = c[v.company][v.country] || ;   //Init if country property does not exist
  c[v.company][v.country][v.employee] = null;                //Add employee property with null value
  return c;
, );

console.log(result);

【参考方案2】：

使用reduce:

const data = ["company":"Google","country":"USA","employee":"John","company":"Amazon","country":"UK","employee":"Arya","company":"Google","country":"KSA","employee":"Cersi","company":"Amazon","country":"USA","employee":"Tyrion","company":"Amazon","country":"USA","employee":"Daenarys","company":"Google","country":"KSA","employee":"Dothrokhi"];
const res = data.reduce((acc,  company, country, employee ) => 
  acc[company] = acc[company] || ;
  acc[company][country] = acc[company][country] || ;
  acc[company][country][employee] = null;
  return acc;
, );
console.log(res);

.as-console-wrapper  max-height: 100% !important; top: auto; 

【参考方案3】：

试试lodash:

// Function to convert an array of an object into an object of null with a key
function convert(array, key, value = null) 
  return Object.fromEntries(array.map(item => [item[key], value]));


// Sample data
const data = [
  "company": "Google", "country": "USA", "employee": "John",
  "company": "Amazon", "country": "UK", "employee": "Arya",
  "company": "Google", "country": "KSA", "employee": "Cersi",
  "company": "Amazon", "country": "USA", "employee": "Tyrion",
  "company": "Amazon", "country": "USA", "employee": "Daenarys",
  "company": "Google", "country": "KSA", "employee": "Dothrokhi"
];

// Using "groupBy" - Group by companies
const companies = _.groupBy(data, obj => obj.company);

// Using "mapValues" - Group each company's data by country
const byCountry = _.mapValues(companies, company => _.groupBy(company, obj => obj.country));

// Convert the array into employees object, or use _.keyBy if you want to keep the original data
const result = _.mapValues(byCountry, company => _.mapValues(company, country => convert(country, 'employee')));

// Result
console.log(result);

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js"></script>