如何在JavaScript中将同职业人员归类到新创建的对象中？

我需要将数组内同职业的人员归类到result对象中，但现有代码无法正确保留所有数据。

原始数据 #

const data = [
    {
        Name: 'Smith',
        age: 25,
        profession: 'Banker'
    },
    {
        Name: 'Alex',
        age: 28,
        profession: 'IT'
    },
    {
        Name: 'John',
        age: 31,
        profession: 'Banker'
    },
    {
        Name: 'Harry',
        age: 26,
        profession: 'Nurse'
    },
];
const result = {};

当前代码 #

const data = [ { Name: "Smith", age: 25, profession: "Banker" }, { Name: "Alex", age: 28, profession: "IT" }, { Name: "John", age: 31, profession: "Banker" }, { Name: "Harry", age: 26, profession: "Nurse" } ];

const result = {};
data.forEach(({ Name, age, profession }) => {
  result[profession] = { Name, age };
});
console.log(result);

问题原因 #

当前代码每次循环都会直接覆盖result[profession]的取值，导致同一职业下只有最后一条人员数据被保留。比如Banker职业，最终只留下John的数据，Smith的数据被覆盖丢失。

解决方案 #

方法一：使用forEach处理数组 #

先检查当前职业对应的属性是否存在，不存在则初始化为空数组，再将当前人员数据推入对应数组：

const data = [
    { Name: 'Smith', age: 25, profession: 'Banker' },
    { Name: 'Alex', age: 28, profession: 'IT' },
    { Name: 'John', age: 31, profession: 'Banker' },
    { Name: 'Harry', age: 26, profession: 'Nurse' }
];

const result = {};
data.forEach(({ Name, age, profession }) => {
  if (!result[profession]) {
    result[profession] = [];
  }
  result[profession].push({ Name, age });
});
console.log(result);

方法二：使用Array.reduce（更简洁） #

利用reduce方法直接构建结果对象：

const data = [
    { Name: 'Smith', age: 25, profession: 'Banker' },
    { Name: 'Alex', age: 28, profession: 'IT' },
    { Name: 'John', age: 31, profession: 'Banker' },
    { Name: 'Harry', age: 26, profession: 'Nurse' }
];

const result = data.reduce((acc, { Name, age, profession }) => {
  acc[profession] = acc[profession] || [];
  acc[profession].push({ Name, age });
  return acc;
}, {});

console.log(result);

内容的提问来源于stack exchange，提问作者Sandeep Kumar