基于sID和nID合并记录count字段的问题求助

需求：基于共同的sId和nId合并记录中的count数据，同一sId和nId的记录分别包含status.count.mr、status.count.ar等数值字段，需将这类记录合并为单个JSON对象，保留各数值字段的有效取值。

原始数据 #

const records = [
{division: {name: "AAA", sId: 1, nId: 111}, status: {dates: {nDate: "02-20", dDate: "03-20"}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "AAA", sId: 1, nId: 222}, status: {dates: {nDate: "02-19", dDate: "03-20"}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "BBB", sId: 2, nId: 111}, status: {dates: {nDate: "02-20", dDate: "03-20"}, count: {emr: 0, mr: 5, ar: 0, totalAR: 0, totalEMR: 0, totalMR: 9}}},
{division: {name: "BBB", sId: 2, nId: 111}, status: {dates: {nDate: "02-20", dDate: "03-20"}, count: {emr: 0, mr: 0, ar: 2, totalAR: 7, totalEMR: 0, totalMR: 0}}},
{division: {name: "BBB", sId: 2, nId: 222}, status: {dates: {nDate: "02-19", dDate: "03-20"}, count: {emr: 0, mr: 3, ar: 0, totalAR: 0, totalEMR: 0, totalMR: 9}}},
{division: {name: "BBB", sId: 2, nId: 222}, status: {dates: {nDate: "02-19", dDate: "03-20"}, count: {emr: 0, mr: 0, ar: 4, totalAR: 7, totalEMR: 0, totalMR: 0}}}
]

尝试的解决方案 #

const mergedMap = new Map();
  for (const record of records) {
    const { sId, nId } = record.division;
    const existingRecord = mergedMap.get(`${sId}-${nId}`);

    if (existingRecord) {
      mergedMap.set(`${sId}-${nId}`, {
        division: existingRecord.division,
        status: {...existingRecord.status, 
          count: {...existingRecord.status.count, ...record.status.count}, 
          dates: {...existingRecord.status.dates, ...record.status.dates},
        },
      });
    } else {
      mergedMap.set(`${sId}-${nId}`, record);
    }
  }
const mergedData = Array.from(mergedMap.values());

期望结果 #

const mergedData = [
{division: {name: "AAA", sId: 1, nId: 111}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "AAA", sId: 1, nId: 222}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "BBB", sId: 2, nId: 111}, status: {dates: {...}, count: {emr: 0, mr: 5, ar: 2, totalAR: 7, totalEMR: 0, totalMR: 9}}},
{division: {name: "BBB", sId: 2, nId: 222}, status: {dates: {...}, count: {emr: 0, mr: 3, ar: 4, totalAR: 7, totalEMR: 0, totalMR: 9}}}
]

实际结果 #

const mergedData = [
{division: {name: "AAA", sId: 1, nId: 111}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "AAA", sId: 1, nId: 222}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 0, totalAR: 0, totalEMR: 10, totalMR: 0}}},
{division: {name: "BBB", sId: 2, nId: 111}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 2, totalAR: 7, totalEMR: 0, totalMR: 0}}},
{division: {name: "BBB", sId: 2, nId: 222}, status: {dates: {...}, count: {emr: 0, mr: 0, ar: 4, totalAR: 7, totalEMR: 0, totalMR: 0}}}
]

问题原因与修正方案 #

问题原因 #

原代码使用对象扩展运算符...直接合并count对象，当第二个记录的字段值为0时，会覆盖第一个记录的非0值（比如mr:5会被后续的mr:0覆盖），导致有效数值丢失。

修正后的代码 #

const mergedMap = new Map();
for (const record of records) {
  const { sId, nId } = record.division;
  const key = `${sId}-${nId}`;
  const existingRecord = mergedMap.get(key);

  if (existingRecord) {
    // 合并count字段，累加数值
    const mergedCount = {...existingRecord.status.count};
    Object.keys(record.status.count).forEach(countKey => {
      mergedCount[countKey] = mergedCount[countKey] + record.status.count[countKey];
    });

    mergedMap.set(key, {
      division: existingRecord.division,
      status: {
        ...existingRecord.status,
        count: mergedCount,
        dates: {...existingRecord.status.dates, ...record.status.dates}
      }
    });
  } else {
    mergedMap.set(key, {...record}); // 浅拷贝避免修改原数据
  }
}
const mergedData = Array.from(mergedMap.values());

说明 #

1. 遍历count的所有键，对每个数值字段进行累加，而非直接覆盖，确保非0值不会被后续的0值覆盖。
2. 对原始记录进行浅拷贝，避免后续修改影响原数据。
3. dates字段保留原合并逻辑，若同一组记录的dates存在差异，会用后续记录的值覆盖，若需保留所有日期可按需调整。

内容的提问来源于stack exchange，提问作者TMA