vue+element导出excel,并修改样式，以及动态合并单元格

首先安装以下三个安装包

npm install --save xlsx（无法设置样式）
npm install --save xlsx-style（支持设置样式）
npm install -S file-saver

注意：如果安装了npm install --save xlsx-style
会报错：This relative module was not found: ./cptable in ./node_modules/xlsx-style@0.8.13@xlsx-style/dist/cpexcel.js

可以直接修改源码：
在\node_modules\xlsx-style\dist\cpexcel.js 807行 的 var cpt = require(’./cpt’ + ‘able’); 改成 var cpt = cptable;

也可以在项目vue.config.js 文件中添加

module.exports = {
  lintOnSave: false,
  css: {
    loaderOptions: {
      sass: {
        data: `@import "~@/styles/variables.scss";`
      }
    }
  },  
  chainWebpack: config => {
  //在 chainWebpack 添加下面的一段代码
    config.externals({ "./cptable": "var cptable" });**
  },
  devServer: {}
};

头部数据以及内容区的数据的合并：

// 计算合并行
//		listData是后台接口返回的数据
      const dataNew = JSON.parse(JSON.stringify(listData))
      const groupData = this.setrowspans(dataNew)
      const mergesArr = []
      // 内容数据合并单元格
      groupData.forEach((item, index) => {
        if (item.rowspan && item.rowspan > 0) {
          const indexNew = index + 3
          // 遍历合并单元格--内容部分
          const cellArr = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M']
          cellArr.forEach(cellItem => {
            const cell = cellItem + indexNew + ':' + cellItem + (indexNew + item.rowspan - 1)
            mergesArr.push(cell)
          })
        }
      })
      import('@/vendor/Export2Excel').then(excel => {
        const multiHeader = [
          ['序号', '应用代号', '应用名称', '发布环境', '包版本', '包大小', '发布结果', '开始时间', '结束时间', '平均用时', '实例数', '预检查', '下载包', '平均用时', '', '', '']
        ]
        const tHeader = ['', '', '', '', '', '', '', '', '', '', '', '', '', '传包', '启动', 'IP', '单台服务器平均用时']
        let merges = ['A1:A2', 'B1:B2', 'C1:C2', 'D1:D2', 'E1:E2', 'F1:F2', 'G1:G2', 'H1:H2', 'I1:I2', 'J1:J2', 'K1:K2', 'L1:L2', 'M1:M2', 'N1:Q1']
        merges = merges.concat(mergesArr)
        const filterVal = ['serialNumber', 'appCode', 'appName', 'environmentCode', 'appPkgVersion', 'packageSize', 'publishResult', 'publishStartTimeStr', 'publishEndTimeStr', 'publishTimeConsumingStr', 'serverTotal', 'precheckConsumingStr', 'downloadPackageConsumingStr', 'downStageStatisticsDetailList1', 'downStageStatisticsDetailList2', 'downStageStatisticsDetailList3', 'downStageStatisticsDetailList4']
        const data = this.formatJson(filterVal, groupData)
        // 数据为空赋值‘-’，不然单元格设置颜色会无效
        for (var key in data) {
          if (data[key]) {
            for (let index = 0; index < data[key].length; index++) {
              data[key][index] = data[key][index] ? data[key][index] : '-'
            }
          }
        }
        // 头部样式
        const hearerStyle = ['A1', 'B1', 'C1', 'D1', 'E1', 'F1', 'G1', 'H1', 'I1', 'J1', 'K1', 'L1', 'M1', 'N1', 'O1', 'P1', 'Q1', 'A2', 'B2', 'C2', 'D2', 'E2', 'F2', 'G2', 'H2', 'I2', 'J2', 'K2', 'L2', 'M2', 'N2', 'O2', 'P2', 'Q2']
        excel.export_json_to_excel({
          multiHeader, // 第一行
          header: tHeader, // 第二行
          data,
          hearerStyle, // 头部样式
          filename: '应用发布各阶段用时统计' + name,
          merges // 单元格合并
        })
      })

// 设置合并行方法： setrowspans(arrData)

// 设置合并行
    setrowspans(arrData) {
      // 先给所有的数据都加一个v.rowspan = 1
      arrData.forEach(v => {
        v.rowspan = 1
      })
      // 双层循环
      for (let i = 0; i < arrData.length; i++) {
        // 内层循环，上面已经给所有的行都加了v.rowspan = 1
        // 这里进行判断
        // 如果当前行的id和下一行的id相等
        // 就把当前v.rowspan + 1
        // 下一行的v.rowspan - 1
        for (let j = i + 1; j < arrData.length; j++) {
          if (arrData[i].pubType !== '' && arrData[i].pubType === arrData[j].pubType) {
            arrData[i].rowspan++
            arrData[j].rowspan--
          }
        }
        // 这里跳过已经重复的数据
        i = i + arrData[i].rowspan - 1
      }
      return arrData
    },

Export2Excel.js文件代码如下：

/* eslint-disable */
import { saveAs } from 'file-saver'
// import XLSX from 'xlsx'
import XLSX from 'xlsx-style'
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;
}

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")
}

export function export_json_to_excel({
  multiHeader = [],
  header,
  data,
  filename,
  hearerStyle = [], //头部样式
  merges = [],
  autoWidth = true,
  bookType = 'xlsx'
} = {}) {
  /* original data */
  filename = filename || 'excel-list'
  data = [...data]
  data.unshift(header);

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

  var ws_name = "SheetJS";
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

  if (merges.length > 0) {
    if (!ws['!merges']) ws['!merges'] = [];
    merges.forEach(item => {
      ws['!merges'].push(XLSX.utils.decode_range(item))
    })
  }

  if (autoWidth) {
    /*设置worksheet每列的最大宽度*/
    const colWidth = data.map(row => row.map(val => {
      /*先判断是否为null/undefined*/
      if (val == null) {
        return {
          'wch': 10
        };
      }
      /*再判断是否为中文*/
      else if (val.toString().charCodeAt(0) > 255) {
        return {
          'wch': val.toString().length * 2
        };
      } else {
        return {
          'wch': val.toString().length
        };
      }
    }))
    /*以第一行为初始值*/
    let result = colWidth[0];
    for (let i = 1; i < colWidth.length; i++) {
      for (let j = 0; j < colWidth[i].length; j++) {
        if (result[j]['wch'] < colWidth[i][j]['wch']) {
          result[j]['wch'] = colWidth[i][j]['wch'];
        }
      }
    }
    ws['!cols'] = result;
  }

  /* add worksheet to workbook */
  wb.SheetNames.push(ws_name);
  wb.Sheets[ws_name] = ws;

  var dataInfo = wb.Sheets[wb.SheetNames[0]];
  
  // 这是表头行的样式
  var tableTitleFont = {
    border: {
      top: {
        style: 'thin',
        color: {rgb: "ffffff"},
      },
      right: {
        style: 'thin',
        color: {rgb: "ffffff"},
      },
      bottom: {
        style: 'thin',
        color: {rgb: "ffffff"},
      },
      left: {
        style: 'thin',
        color: {rgb: "ffffff"},
      },
    },
    font: {
      sz: 12,
      color: {rgb: "ffffff"},
      bold: true,
    },
    alignment: {
      horizontal: "center",
      vertical: "center"
    },
    fill: {
      fgColor: {rgb: "017ede"},
    },
  };
  for (var i = 0; i < hearerStyle.length; i++) {
    dataInfo[hearerStyle[i]].s = tableTitleFont;
  }
  var wbout = XLSX.write(wb, {
    bookType: bookType,
    bookSST: false,
    type: 'binary'
  });
  saveAs(new Blob([s2ab(wbout)], {
    type: "application/octet-stream"
  }), `${filename}.${bookType}`);
}