根据字段值对数组进行分组，并将分组的值推送到数组中

function groupArrayByField(arr, field) {
  const groups = {};
  
  for (let i = 0; i < arr.length; i++) {
    const item = arr[i];
    const value = item[field];
    
    if (!groups.hasOwnProperty(value)) {
      groups[value] = [item];
    } else {
      groups[value].push(item);
    }
  }
  
  return Object.values(groups);
}

// 示例用法
const originalArray = [
  { id: 1, name: 'Alice', group: 'A' },
  { id: 2, name: 'Bob', group: 'B' },
  { id: 3, name: 'Charlie', group: 'A' },
  { id: 4, name: 'Dave', group: 'C' },
  { id: 5, name: 'Eve', group: 'B' }
];

const groupedArray = groupArrayByField(originalArray, 'group');
console.log(groupedArray);

[
  [
    { id: 1, name: 'Alice', group: 'A' },
    { id: 3, name: 'Charlie', group: 'A' }
  ],
  [
    { id: 2, name: 'Bob', group: 'B' },
    { id: 5, name: 'Eve', group: 'B' }
  ],
  [
    { id: 4, name: 'Dave', group: 'C' }
  ]
]