vue导出excel表格，多级表头

需求：

image.png

要求导出如上图所示的表格文件。
实现代码：

export default {
  name: "exportExcelTemplate",
  data() {
    return {
      tableData: [
        [{
          phase: "相位1",
          desc: "南北直行，北口右转， 南北人行",
          green: 10,
          yellow: 10,
          red: 10
        },]
      ]
    };
  },
  created() {
    this.initTableData();
  },
  methods: {
    initTableData() {
      let tableData = [];
      let phaseIndex = [4, 4, 4, 4];
      for (let i = 0; i < 4; i++) {
        let temp = [];
        for (let j = 0; j < phaseIndex[i]; j++) {
          temp.push({
            phase: "相位" + j,
            desc: "南北直行，北口右转， 南北人行" + j,
            green: i * j,
            yellow: i * j,
            red: i * j
          });
        }
        temp.push({
          type: "time",
          time: "09:00:18:30"
        });
        tableData.push(temp);
      }
      this.tableData = tableData;
    },
    getExcelDataList() {
      let result = [];
      // 路口信息
      result.push(["路口名称"], "市心南路-南四路");
      return result;
    },
    formatJson(filterVal, jsonData) {
      return jsonData.map(v => filterVal.map(j => {
        return v[j]
      }))
    },
    // 获取相位方案的多级头部
    getPhaseMultiHeader() {
      let result = [];
      let merges = [];
      let startIndex = 4;
      for (let i = 0; i < this.tableData.length; i++) {
        startIndex ++;
        result.push(["", "", "绿灯时间", "黄灯时间", "红灯时间"]);
        for (let j = 0; j < this.tableData[i].length; j++) {
          startIndex ++;
          if (this.tableData[i][j].type !== "time") { // 非时段处理
            result.push([
              this.tableData[i][j].phase,
              this.tableData[i][j].desc,
              this.tableData[i][j].green,
              this.tableData[i][j].yellow,
              this.tableData[i][j].red]);
          } else { // 时段处理
            result.push(["时段", this.tableData[i][j].time, "", "", ""]);
            merges.push(`B${startIndex}:E${startIndex}`);
          }
        }
      }
      return [result, merges];
    },
    exportExcel() {
      require.ensure([], () => {
        const { export_json_to_excel } = require("@/common/vendor/Export2Excel");
        let multiHeader = [
          ["信号控制方案", "", "", "", ""], //第一行
          ["路口名称", "市心南路-南四路", "", "", ""], // 第二行
          ["运行日期", "周六,周日", "", "", ""], // 第三行
          ["时段", "07:00-09:00;", "", "", ""], // 第四行
          ...this.getPhaseMultiHeader()[0]
        ];
        const header = []; // 最后一行的表头数据
        const filterVal = [];
        const list = this.tableData;
        const data = this.formatJson(filterVal, list)
        const merges = ["A1:E1", "B2:E2", "B3:E3", "B4:E4", ...this.getPhaseMultiHeader()[1]] // 合并单元格的数据，如何合并参考上面图片的蓝色背景部分
        export_json_to_excel({
          multiHeader,
          header,
          merges,
          data,
          filename: "信号控制方案"
        })
      });
    }
  }
}

参考资料：https://www.liyangzone.com/2020/02/27/%E5%89%8D%E7%AB%AF/%E4%BD%BF%E7%94%A8js-xlsx%E6%8F%92%E4%BB%B6%E5%AF%BC%E5%87%BA%E5%A4%9A%E7%BA%A7%E8%A1%A8%E5%A4%B4excel/