JavaScript：按物件中的屬性對物件陣列進行分組-有解無憂

如果我有一個像下面這樣的 js 陣列，有沒有一種簡單的方法可以按年齡重新分組陣列值？我試圖將它減少為一個陣列，但它沒有幫助。它按年齡或姓名重新分組

let employees = [
 {
  firstName:"Zion",
  lastName: "Rosy",
  age: 25,
  joinedDate:"January 24, 2020",
 },

 {
  firstName: "Ana",
  lastName: "Rosy",
  age: 25,
  joinedDate: "January 15, 2019",
 },

 {
  firstName: "Zion",
  lastName:"Albert",
  age: 30,
  joinedDate:"February 15, 2011",
 },
];

像這樣按年齡重新分組：

let organizedByAge =
 {
  25: [
 {
  firstName:"Zion",
  lastName: "Rosy",
  age: 25,
  joinedDate:"January 24, 2020",
 },
 {
  firstName: "Ana",
  lastName: "Rosy",
  age: 25,
  joinedDate: "January 15, 2019",
 },
  ],

  30: [
   {
    firstName:"Zion",
    lastName:"Albert",
    age: 30,
    joinedDate:"February 15, 2011",
   },
  ],
 };

uj5u.com熱心網友回復：

const groupByKey = (_data, _key) => {
  return _data.reduce((result, next) => {
    const key = next[_key];
    result[key] = result[key]?.length ? [...result[key], next] : [next];
    return result;
  }, {});
  }

 console.warn(groupByKey(employees, 'age'));

uj5u.com熱心網友回復：

有沒有一種簡單的方法可以按年齡重新分組陣列值？

在重寫陣列和物件時，最直接和可讀的方法通常是使用一個簡單的for回圈：

for (let i = 0; i < employees.length; i  ) {
  
  const age = employees[i]['age'];
  
  if (organizedByAge.hasOwnProperty(age)) {
    organizedByAge[age].push(employees[i]);
  }
  
  else {
    organizedByAge[age] = [];
    organizedByAge[age][0] = employees[i];
  }
}

作業示例：

let employees = [
 {
  firstName:"Zion",
  lastName: "Rosy",
  age: 25,
  joinedDate:"January 24, 2020",
 },

 {
  firstName: "Ana",
  lastName: "Rosy",
  age: 25,
  joinedDate: "January 15, 2019",
 },

 {
  firstName: "Zion",
  lastName:"Albert",
  age: 30,
  joinedDate:"February 15, 2011",
 },
];

let organizedByAge = {};

for (let i = 0; i < employees.length; i  ) {
  
  const age = employees[i]['age'];
  
  if (organizedByAge.hasOwnProperty(age)) {
    organizedByAge[age].push(employees[i]);
  }
  
  else {
    organizedByAge[age] = [];
    organizedByAge[age][0] = employees[i];
  }
}

console.log(organizedByAge);

uj5u.com熱心網友回復：

使用Array#reduce：

const employees = [
  { firstName:"Zion", lastName: "Rosy", age: 25, joinedDate:"January 24, 2020" },
  { firstName: "Ana", lastName: "Rosy", age: 25, joinedDate: "January 15, 2019" },
  { firstName: "Zion", lastName:"Albert", age: 30, joinedDate:"February 15, 2011" }
];

const organizedByAge = employees.reduce((map, e) => ({
  ...map,
  [e.age]: [...(map[e.age] ?? []), e]
}), {});

console.log(organizedByAge);

轉載請註明出處，本文鏈接：https://www.uj5u.com/qiye/406981.html

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