根据相同的值对数组进行分组

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

// 示例数组
const data = [
  { name: 'Alice', age: 25 },
  { name: 'Bob', age: 30 },
  { name: 'Charlie', age: 25 },
  { name: 'David', age: 30 }
];

// 按年龄分组
const groupedData = groupBy(data, 'age');
console.log(groupedData);

{
  '25': [
    { name: 'Alice', age: 25 },
    { name: 'Charlie', age: 25 }
  ],
  '30': [
    { name: 'Bob', age: 30 },
    { name: 'David', age: 30 }
  ]
}

function groupBy(array, key) {
  return array.reduce((result, item) => {
    const value = item[key] || 'unknown';
    if (!result[value]) {
      result[value] = [];
    }
    result[value].push(item);
    return result;
  }, {});
}

function groupBy(array, key) {
  return array.reduce((result, item) => {
    const value = String(item[key]);
    if (!result[value]) {
      result[value] = [];
    }
    result[value].push(item);
    return result;
  }, {});
}