vue2 xlsx结合file-saver实现JSON导出excel 支持导出多sheet

 npm install xlsx -s
 npm install file-saver  -s

import { saveAs } from "file-saver";
import * as XLSX from "xlsx";
function generateArray(table) {
  var out = [];
  var rows = table.querySelectorAll("tr");
  var ranges = [];
  for (var R = 0; R < rows.length; ++R) {
    var outRow = [];
    var row = rows[R];
    var columns = row.querySelectorAll("td");
    for (var C = 0; C < columns.length; ++C) {
      var cell = columns[C];
      var colspan = cell.getAttribute("colspan");
      var rowspan = cell.getAttribute("rowspan");
      var cellValue = cell.innerText;
      if (cellValue !== "" && cellValue == +cellValue) cellValue = +cellValue;

      //Skip ranges
      ranges.forEach(function (range) {
        if (
          R >= range.s.r &&
          R <= range.e.r &&
          outRow.length >= range.s.c &&
          outRow.length <= range.e.c
        ) {
          for (var i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null);
        }
      });
      //Handle Row Span
      if (rowspan || colspan) {
        rowspan = rowspan || 1;
        colspan = colspan || 1;
        ranges.push({
          s: {
            r: R,
            c: outRow.length,
          },
          e: {
            r: R + rowspan - 1,
            c: outRow.length + colspan - 1,
          },
        });
      }
      //Handle Value
      outRow.push(cellValue !== "" ? cellValue : null);
      //Handle Colspan
      if (colspan) for (var k = 0; k < colspan - 1; ++k) outRow.push(null);
    }
    out.push(outRow);
  }
  return [out, ranges];
}
function datenum(v, date1904) {
  if (date1904) v += 1462;
  var epoch = Date.parse(v);
  return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
}

function sheet_from_array_of_arrays(data, opts) {
  var ws = {};
  var range = {
    s: {
      c: 10000000,
      r: 10000000,
    },
    e: {
      c: 0,
      r: 0,
    },
  };
  for (var R = 0; R != data.length; ++R) {
    for (var C = 0; C != data[R].length; ++C) {
      if (range.s.r > R) range.s.r = R;
      if (range.s.c > C) range.s.c = C;
      if (range.e.r < R) range.e.r = R;
      if (range.e.c < C) range.e.c = C;
      var cell = {
        v: data[R][C],
      };
      if (cell.v == null) continue;
      var cell_ref = XLSX.utils.encode_cell({
        c: C,
        r: R,
      });

      if (typeof cell.v === "number") cell.t = "n";
      else if (typeof cell.v === "boolean") cell.t = "b";
      else if (cell.v instanceof Date) {
        cell.t = "n";
        cell.z = XLSX.SSF._table[14];
        cell.v = datenum(cell.v);
      } else cell.t = "s";

      ws[cell_ref] = cell;
    }
  }
  if (range.s.c < 10000000) ws["!ref"] = XLSX.utils.encode_range(range);
  return ws;
}
function Workbook() {
  if (!(this instanceof Workbook)) return new Workbook();
  this.SheetNames = [];
  this.Sheets = {};
}
function s2ab(s) {
  var buf = new ArrayBuffer(s.length);
  var view = new Uint8Array(buf);
  for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xff;
  return buf;
}
/**
* 根据页面表格ID导出excel
*/
export function export_table_to_excel(id) {
  var theTable = document.getElementById(id);
  var oo = generateArray(theTable);
  var ranges = oo[1];
  /* original data */
  var data = oo[0];
  var ws_name = "SheetJS";
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);
  /* add ranges to worksheet */
  // ws['!cols'] = ['apple', 'banan'];
  ws["!merges"] = ranges;
  /* add worksheet to workbook */
  wb.SheetNames.push(ws_name);
  wb.Sheets[ws_name] = ws;
  var wbout = XLSX.write(wb, {
    bookType: "xlsx",
    bookSST: false,
    type: "binary",
  });

  saveAs(
    new Blob([s2ab(wbout)], {
      type: "application/octet-stream",
    }),
    "test.xlsx"
  );
}

//主要修改此函数内的方法
// json导出excel

export function export_json_to_excel({
  multiHeader = [],
  header,
  data,
  sheetname,
  filename,
  merges = [],
  autoWidth = true,
  bookType = "xlsx",
} = {}) {
  /* original data */
  filename = filename || "excel-list";
  data = [...data];

  for (var i = 0; i < header.length; i++) {
    data[i].unshift(header[i]);
  }

  // data.unshift(header)

  for (let i = multiHeader.length - 1; i > -1; i--) {
    data.unshift(multiHeader[i]);
  }

  var ws_name = sheetname;
  var wb = new Workbook(),
    ws = [];
  for (var j = 0; j < header.length; j++) {
    ws.push(sheet_from_array_of_arrays(data[j]));
  }

  if (merges.length > 0) {
    merges.forEach((item, idx) => {
      if (!ws[idx]["!merges"]) ws[idx]["!merges"] = [];
      ws[idx]["!merges"].push(XLSX.utils.decode_range(item));
    });
  }
  // console.log("width", autoWidth)
  if (autoWidth) {
    /*设置worksheet每列的最大宽度*/
    var colWidth = [];
    for (var k = 0; k < header.length; k++) {
      colWidth.push(
        data[k].map((row) =>
          row.map((val) => {
            /*先判断是否为null/undefined*/
            if (val == null) {
              return {
                wch: 10,
              };
            } else if (val.toString().charCodeAt(0) > 255) {
              /*再判断是否为中文*/
              return {
                wch: val.toString().length * 2,
              };
            } else {
              return {
                wch: val.toString().length,
              };
            }
          })
        )
      );
    }

    /*以第一行为初始值*/
    let result = [];
    for (var k = 0; k < colWidth.length; k++) {
      result[k] = colWidth[k][0];
      for (let i = 1; i < colWidth[k].length; i++) {
        for (let j = 0; j < colWidth[k][i].length; j++) {
          if (result[k][j]["wch"] < colWidth[k][i][j]["wch"]) {
            result[k][j]["wch"] = colWidth[k][i][j]["wch"];
          }
        }
      }
    }
    // 分别给sheet表设置宽度
    for (var l = 0; l < result.length; l++) {
      ws[l]["!cols"] = result[l];
    }
  }

  /* add worksheet to workbook */
  for (var k = 0; k < header.length; k++) {
    wb.SheetNames.push(ws_name[k]);
    wb.Sheets[ws_name[k]] = ws[k];
  }

  var wbout = XLSX.write(wb, {
    bookType: bookType,
    bookSST: false,
    type: "binary",
  });
  saveAs(
    new Blob([s2ab(wbout)], {
      type: "application/octet-stream",
    }),
    `${filename}.${bookType}`
  );
}

/**
     * excel 导出
     * */
    exportExcel() {
      let exportTabs = {
        mz: {
          data: [],
        },
        tyz: {
          data: [],
        },
        rqyh: {
          data: [],
        },
      };
      Object.keys(serverData).filter((key) => {
        exportTabs[key].data = exportTabs[key].data.concat(
          serverData[key].data
        );
      });
      //组件数据 以sheet为维度
      let sheetArr = [];
      let merges = [];

      Object.keys(exportTabs).filter((key) => {
        // 构建每个sheet的表头
        let newTableHead = this.columns;
        let tempAllData = [];
        if (this.activeName === key) {
          tempAllData = this.tableData;
        } else {
          tempAllData = exportTabs[key].data;
        }
        // 构建数据字段
        const { filterVal, tHeader } =
          this.setExcelFilterValAndTheader(newTableHead);
        // 追加上误差汇总  if (key === "mz")
        this.AddTotalError(tempAllData, filterVal);
        // 合并单元格
        const merge = this.merageTabCol(tempAllData, tHeader);
        merges.push(merge);
        let label = "门站";
        if (key === "tyz") label = "调压站";
        if (key === "rqyh") label = "用户";
        sheetArr.push({
          // sheet表头部
          tHeader: tHeader,
          // 表的数据字段
          filterVal: filterVal,
          // 表的整体json数据
          tableDatas: tempAllData,
          // 表的sheet名字
          sheetName: label,
        });
      });
      console.log("sheetArr", sheetArr);
      const filename = `${this.detailReturnIds.topologyVersionName}  仪表检验`;
      import("@/utils/Export2MultipleSheetExcel")
        .then((excel) => {
          var tHeader = [];
          var dataArr = [];
          var sheetnames = [];
          for (var i in sheetArr) {
            tHeader.push(sheetArr[i].tHeader);
            dataArr.push(
              this.formatJson(sheetArr[i].filterVal, sheetArr[i].tableDatas)
            );
            sheetnames.push(sheetArr[i].sheetName);
          }
          console.log("tHeader", tHeader);
          console.log("dataArr", dataArr);
          console.log("sheetnames", sheetnames);
          console.log("merges", merges);
          excel.export_json_to_excel({
            header: tHeader,
            data: dataArr,
            sheetname: sheetnames,
            filename: filename,
            merges: merges,
            autoWidth: true,
            bookType: "xlsx",
          });
        })
        .catch((e) => {
          console.log(e);
          this.$message.error("获取表格数据失败，请稍等重试...");
        });
    },
    setExcelFilterValAndTheader(_data) {
      let filterVal = [];
      let tHeader = [];
      _data.filter((item) => {
        let dataIndex = item.dataIndex;
        filterVal.push(dataIndex);
        tHeader.push(item.title);
      });
      return { filterVal, tHeader };
    },
    AddTotalError(_data, filterVal) {
      let errStr = "";
      errStr += `压力最大误差值:${
        this.currentErrorObj.pressMaxError == 0
          ? "0%"
          : `${(this.currentErrorObj.pressMaxError * 100).toFixed(2)}%`
      }`;
      (errStr += `  压力平均误差值:${
        this.currentErrorObj.pressAvergeError == 0
          ? "0%"
          : `${(this.currentErrorObj.pressAvergeError * 100).toFixed(2)}%`
      }`),
        (errStr += `  流量最大误差值:${
          this.currentErrorObj.fluMaxError == 0
            ? "0%"
            : `${(this.currentErrorObj.fluMaxError * 100).toFixed(2)}%`
        }`);
      errStr += `  流量平均误差值:${
        this.currentErrorObj.fluAvergeError == 0
          ? "0%"
          : `${(this.currentErrorObj.fluAvergeError * 100).toFixed(2)}%`
      }`;
      let errObj = {};
      filterVal.filter((f, idx) => {
        errObj[f] = "";
        if (idx === 0) errObj[f] = errStr;
      });
      _data.push(errObj);
    },
    merageTabCol(_data, tHeader) {
      // 合并单元格
      const englishWordList = [
        "A",
        "B",
        "C",
        "D",
        "E",
        "F",
        "G",
        "H",
        "I",
        "J",
        "K",
        "L",
        "M",
        "N",
        "O",
        "P",
        "Q",
        "R",
        "S",
        "T",
        "U",
        "V",
        "W",
        "X",
        "Y",
        "Z",
      ];
      let merges = `A${_data.length + 1}:${
        englishWordList[tHeader.length - 1]
      }${_data.length + 1}`;
      return merges;
    },
    formatJson(filterVal, jsonData) {
      return jsonData.map((v) => filterVal.map((j) => v[j]));
    },