如何用reduce合并对象数组生成指定结构？已写代码遇阻

我尝试用reduce把对象数组转成预期格式，目前实现了按validFrom字段分组，但后续推进不了，试了map也没效果，求帮忙。

输入数组 #

const inputArray = [
  {
    "day": "Wednesday",
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Tuesday",
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Sunday",
    "closeTime": "1630",
    "openTime": "0845",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Thursday",
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Friday",
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Saturday",
    "closeTime": "1630",
    "openTime": "0845",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": "Monday",
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  }
];

已用代码 #

let clubbedArray = normalData.reduce((acc, temp) => { let { validFrom, day } = temp; return {...acc, [validFrom]: [...(acc[validFrom] || []), day]}; }, {});

预期输出 #

[
  {
    "day": [
      "Friday",
      "Wednesday",
      "Monday",
      "Tuesday",
      "Thursday"
    ],
    "closeTime": "2000",
    "openTime": "0800",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  },
  {
    "day": [
      "Saturday",
      "Sunday"
    ],
    "closeTime": "1630",
    "openTime": "0845",
    "validFrom": "2001-09-19",
    "validTo": "2099-12-31"
  }
]

解决方案 #

你的核心需求是按openTime、closeTime、validFrom、validTo这一组相同字段来合并day数组，之前的代码仅按validFrom分组，忽略了时间规则的组合，所以无法得到预期结果。

可以通过调整reduce的分组key来实现：

const result = Object.values(inputArray.reduce((acc, item) => {
  // 用所有公共字段组合作为分组标识，确保相同规则的项被分到同一组
  const groupKey = `${item.openTime}-${item.closeTime}-${item.validFrom}-${item.validTo}`;
  
  if (!acc[groupKey]) {
    // 初始化分组对象，复制公共字段并将day设为空数组
    acc[groupKey] = {
      ...item,
      day: []
    };
  }
  
  // 将当前项的day添加到分组的day数组中
  acc[groupKey].day.push(item.day);
  
  return acc;
}, {}));

代码说明 #

1. 分组key设计：用openTime+closeTime+validFrom+validTo的组合字符串作为key，确保只有完全相同的时间规则才会被合并。
2. 初始化分组：当首次遇到某个分组key时，创建新的分组对象，复制当前项的公共字段，并初始化day数组。
3. 合并day字段：后续遇到同组的项时，直接将day字段推入分组的day数组。
4. 转换为数组：最后用Object.values()将分组对象转换为数组，得到预期的输出格式。

内容的提问来源于stack exchange，提问作者GD19