JS按branch、environment分组对象 拼接pool字段并去重

现有对象数组，需将branch（分支）、environment（环境）字段值相同的对象分组合并，拼接对应pool（资源池）字段值，最终移除重复对象。使用reduce实现时因返回单个对象导致其余对象遗漏，需匹配如下输入输出要求：

输入数据 #

const data = [
  {
    branch: "master",
    environment: "dev",
    pool: "6g",
    service: "amex",
  },
  {
    branch: "master",
    environment: "dev",
    pool: "6g",
    service: "amex",
  },
  {
    branch: "feature/rest",
    environment: "dev",
    pool: "2g",
    service: "amex",
  },
  {
    branch: "master",
    environment: "dev",
    pool: "4g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "9g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "1g",
    service: "amex",
  },
];

预期输出 #

const result = [
  {
    branch: "master",
    environment: "dev",
    pool: "6g, 4g",
    service: "amex",
  },
  {
    branch: "feature/rest",
    environment: "dev",
    pool: "2g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "9g,1g",
    service: "amex",
  },
];

之前用reduce出现对象遗漏，核心问题是累加器的数据结构选择错误：不要直接把单个合并对象作为累加返回值，先用键值对映射对象做临时分组存储，分组完成后再将映射值转为数组即可，全程不会丢失数据。
具体实现逻辑：

• 初始化reduce累加器为空对象，作为临时分组表
• 遍历每个元素时，用${branch}_${environment}拼接生成分组唯一key
• 若key不存在，将当前元素浅拷贝后存入分组表，初始化对应分组
• 若key已存在，判断当前元素的pool值是否已在分组的pool字段中存在，不存在则追加拼接，避免重复值
• 遍历完成后，用Object.values()提取分组表的所有值，即为最终结果数组

完整代码 #

const result = Object.values(
  data.reduce((groupMap, item) => {
    const groupKey = `${item.branch}_${item.environment}`;
    if (!groupMap[groupKey]) {
      groupMap[groupKey] = { ...item };
    } else {
      // 兼容逗号后带/不带空格的格式做去重判断
      const existingPools = groupMap[groupKey].pool.split(/,\s*/);
      if (!existingPools.includes(item.pool)) {
        // 可按需修改拼接分隔符，示例用逗号+空格匹配通用格式
        groupMap[groupKey].pool += `, ${item.pool}`;
      }
    }
    return groupMap;
  }, {})
);

运行代码后输出结果完全匹配预期：

• 重复的对象、重复的pool值会被自动去重
• 仅当branch和environment两个字段同时匹配时才会归入同一分组
• 最终返回标准数组格式，无对象遗漏问题

内容的提问来源于stack exchange，提问作者giiyiraj