如何在JS中按name和status过滤对象数组并统计数量

现有如下数组数据：

[
  {service: { name: "Home" },status: "Generated", feeCharged:{id:1,fee:2}},
  {service: { name: " Photography" },status: "requested",feeCharged:{id:2,fee:24}},
  {service: { name: "Electrical" },status: "requested",feeCharged:{id:6,fee:42}},
  {service: { name: "Electrical" },status: "Completed",feeCharged:{id:66,fee:23} },
  {service: { name: " Photography" },status: "Completed",feeCharged:{id:78,fee:11}},
  {service: { name: "Home" },status: "Generated",feeCharged:{id:45,fee:234}},
  {service: { name: "Electrical" }, status: "requested",feeCharged:{id:77,fee:3} },
  {service: { name: "Electrical" }, status: "requested",feeCharged:{id:4,fee:33} }
]

需要按service.name和status两个字段分组，合并相同组合的对象并添加count统计数量，最终期望结果：

[
  { name: "Home", status: "Generated", count: 2 },
  { name: "Photography", status: "requested", count: 1 },
  { name: "Photography", status: "Completed", count: 1 },
  { name: "Electrical", status: "requested", count: 3 },
  { name: "Electrical", status: "Completed", count: 1 }
]

尝试的代码未达到预期：

let answer = [];

data.forEach((x) => {
  if (!answer.some((y) => y.name === x.service.name)) {
    let newAnswer = {};
    newAnswer.name = x.service.name;
    newAnswer.value = 1;
    answer.push(newAnswer);
  } else {
    let existAnswer = answer.find((y) => y.name === x.service.name);
    existAnswer.value++;
  }
});

你当前的代码只依据service.name进行分组统计，没有将status纳入分组条件，导致同一service.name下不同status的项会被错误合并，自然得不到预期结果。另外原数据中部分service.name带有前置空格，需要做去除处理以匹配期望结果。

可以使用Array.reduce()方法实现分组统计，同时处理名称的空格问题：

const data = [
  {service: { name: "Home" },status: "Generated", feeCharged:{id:1,fee:2}},
  {service: { name: " Photography" },status: "requested",feeCharged:{id:2,fee:24}},
  {service: { name: "Electrical" },status: "requested",feeCharged:{id:6,fee:42}},
  {service: { name: "Electrical" },status: "Completed",feeCharged:{id:66,fee:23} },
  {service: { name: " Photography" },status: "Completed",feeCharged:{id:78,fee:11}},
  {service: { name: "Home" },status: "Generated",feeCharged:{id:45,fee:234}},
  {service: { name: "Electrical" }, status: "requested",feeCharged:{id:77,fee:3} },
  {service: { name: "Electrical" }, status: "requested",feeCharged:{id:4,fee:33} }
];

// 用reduce生成分组统计的对象，键为name和status的组合
const grouped = data.reduce((acc, item) => {
  const name = item.service.name.trim(); // 去除名称前后空格
  const status = item.status;
  const key = `${name}-${status}`; // 生成唯一分组键

  if (acc[key]) {
    acc[key].count++;
  } else {
    acc[key] = { name, status, count: 1 };
  }

  return acc;
}, {});

// 将分组对象转为数组
const answer = Object.values(grouped);

console.log(answer);

代码说明 #

1. 分组键生成：通过name和status拼接成唯一字符串作为键，确保同一名称+状态的项被归为一组。
2. 空格处理：使用trim()去除service.name前后的空格，匹配期望结果中的名称格式。
3. 统计逻辑：遍历数组时，若分组已存在则计数+1，否则创建新的分组项并初始化计数为1。
4. 结果转换：通过Object.values()将分组对象转为最终的数组格式。

内容的提问来源于stack exchange，提问作者someone