前端表格导出合并一（XLSX）

业务需要，做了个前端导出，使用了XLSX，由于有部分数据长度不固定，所以合并范围需要动态计算。
后面需要调整样式，发现 XLSX 开源版本不支持，切换到国产 ExcelJS，并基于此封装了一个工具类
ExcelJSuu, 封装简化了插件提供的函数，并可以根据页面渲染所需的相同树形数据结构直接
计算出合并范围，最后封装完整后只需要直接传入表头和表格数据即可。

/**
 *
 * @param queryHeader 第一排表头数组
 */
async function exportTable(queryHeader = tableHeader1.value) {
  const header1 = queryHeader ?? [
    "学校",
    "考试",
    "考试时间",
    "年级",
    "班级",
    "科目",
    "考试总分",
  ];

  const header2 = ["学号", "姓名", "班级"];

  const dynamic = ["分数", "联考排名", "学校排名", "班级排名"];

  const headers: [
    headerRow1: string[],
    headerRow2: string[],
    headerRow2: string[]
  ] = [[], [...header2], new Array(header2.length + 1)];
  const [headerRow1, headerRow2, headerRow3] = headers;

  const params = deepCopy(showScoreParams.value);
  params.limit = 100000000;

  const { items } = await api.Internal.ScoreAnalysis.GetScoreRanking_PostAsync(
    params,
    []
  );
  if (items?.length == 0) return;

  const [firstItem] = items;

  firstItem.scoreDetail
    .map((e) => e.subjectName)
    .forEach((subjectName) => {
      headerRow2.push(...[subjectName, ...new Array(dynamic.length - 1)]);
    });

  const interval = Math.floor(headerRow2.length / header1.length) - 1; // 间隔

  header1.reduce((pre, cur) => {
    // pre.push(...[cur, ...new Array(interval)]);
    headerRow1.push(...[cur, ...new Array(interval)]);
    return pre;
  }, []);

  for (let i = 0; i < firstItem.scoreDetail.length; i++) {
    headerRow3.push(...dynamic);
  }

  const sheet = items.reduce((pre, cur) => {
    const {
      studentName,
      internalStudentNumber,
      schoolName,
      className,
      examName,
    } = cur.info;

    const row: (string | number)[] = [
      internalStudentNumber,
      studentName,
      className,
    ];

    cur.scoreDetail.forEach((item) => {
      const { subjectName, score, unionExamRanking, ranking, classRanking } =
        item;

      row.push(...[score, unionExamRanking, ranking, classRanking]);
    });

    pre.push(row);

    return pre;
  }, []);

  sheet.unshift(...headers);

  const ws = utils.aoa_to_sheet(sheet);

  /**
   * 构造固定列，无定数列表头所合并行列坐标范围
   */
  const headerRow1MG = rangeArray(0, headerRow1.length - 1).flatMap(
    (num, i) => {
      if (i % (interval + 1) === 0) {
        return {
          s: { c: num, r: 0 },
          e: { c: num + interval, r: 0 },
        };
      }
      return [];
    }
  );

  const headerRow2MG = rangeArray(0, header2.length - 1).map((num) => ({
    s: { c: num, r: 1 },
    e: { c: num, r: 2 },
  }));

  const headerRow2DynamicMG = rangeArray(
    header2.length,
    headerRow2.length
  ).flatMap((num, i) => {
    if (i % dynamic.length === 0) {
      return {
        s: { c: num, r: 1 },
        e: { c: num + dynamic.length - 1, r: 1 },
      };
    }
    return [];
  });

  ws["!merges"] = [
    ...headerRow1MG,
    ...headerRow2MG.concat(headerRow2DynamicMG),
  ];

  ws["!cols"] = headerRow3.map((e) => ({ wpx: 120 }));
  ws["!rows"] = headerRow3.map((e) => ({ hpx: 32 }));

  const wb = utils.book_new();
  utils.book_append_sheet(wb, ws, "显示成绩");
  writeFile(wb, "学生成绩信息.xlsx");
}