对数组中对象的属性进行分组

const arr = [
  { name: 'Alice', age: 25, gender: 'female' },
  { name: 'Bob', age: 30, gender: 'male' },
  { name: 'Charlie', age: 35, gender: 'male' },
  { name: 'David', age: 25, gender: 'male' },
  { name: 'Eve', age: 30, gender: 'female' }
];

const groupBy = (array, property) => {
  return array.reduce((result, obj) => {
    const key = obj[property];
    if (!result[key]) {
      result[key] = [];
    }
    result[key].push(obj);
    return result;
  }, {});
};

const grouped = groupBy(arr, 'age');
console.log(grouped);

{
  25: [
    { name: 'Alice', age: 25, gender: 'female' },
    { name: 'David', age: 25, gender: 'male' }
  ],
  30: [
    { name: 'Bob', age: 30, gender: 'male' },
    { name: 'Eve', age: 30, gender: 'female' }
  ],
  35: [
    { name: 'Charlie', age: 35, gender: 'male' }
  ]
}