前端导出多级表头

前端导出多级表头

今天在技术交流群里面看到有人问到了这一块，我之前看过一些关于这样的代码，我就直接给他上了代码，自己又重新练习里一遍

这是结合elementUI来写的一个表格。

先看一下练习的是这样的效果

首先还是要安装依赖

npm install xlsx file-saver -S
npm install script-loader -S -D

直接上代码
1、需要一个Export2Excel.js文件

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

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

2、下面就是HTML和JS部分

<template>
  <div>
    <el-button type="primary" @click.native="outExcel">导出</el-button>
    <el-table :data="tableData" style="width: 100%">
      <el-table-column prop="date" label="日期" width="150"> </el-table-column>
      <el-table-column label="配送信息">
        <el-table-column prop="name" label="姓名" width="120">
        </el-table-column>
        <el-table-column label="地址">
          <el-table-column prop="province" label="省份" width="120">
          </el-table-column>
          <el-table-column prop="city" label="市区" width="120">
          </el-table-column>
          <el-table-column prop="address" label="地址" width="300">
          </el-table-column>
          <el-table-column prop="zip" label="邮编" width="120">
          </el-table-column>
        </el-table-column>
      </el-table-column>
    </el-table>
  </div>
</template>

<script>
export default {
  data() {
    return {
      tableData: [
        {
          date: "2016-05-03",
          name: "王小虎",
          province: "上海",
          city: "普陀区",
          address: "上海市普陀区",
          zip: 200333,
        },
        {
          date: "2016-05-02",
          name: "王小虎",
          province: "上海",
          city: "普陀区",
          address: "上海市普陀区",
          zip: 200333,
        },
        {
          date: "2016-05-04",
          name: "王小虎",
          province: "上海",
          city: "普陀区",
          address: "上海市普陀区",
          zip: 200333,
        },
        {
          date: "2016-05-01",
          name: "王小虎",
          province: "上海",
          city: "普陀区",
          address: "上海市普陀区",
          zip: 200333,
        },
        {
          date: "2016-05-08",
          name: "王小虎",
          province: "上海",
          city: "普陀区",
          address: "上海市普陀区",
          zip: 200333,
        },
      ],
    };
  },
  methods: {
    outExcel() {
        //../untils/Export2Excel 这个是根据你自己存放Export2Excel.js文件的路径来写的
      import("../untils/Export2Excel").then((excel) => {
        const multiHeader = [
          ["日期", "配送信息", "", "", "", ""],//第一行表头
          ["", "姓名", "地址", "", "", ""],//第二行表头
        ];
        const tHeader = ["", "", "省份", "市区", "地址", "邮编"]; //最后一行的表头
        const filterVal = [
          "date",
          "name",
          "province",
          "city",
          "address",
          "zip",
        ];
        const list = this.tableData; //这个是你循环数据到页面上的的变量名
        const data = this.formatJson(filterVal, list);
        const merges = ["A1:A3", "B1:F1", "B2:B3", "C1:F1","C2:F2"];
        excel.export_json_to_excel({
          multiHeader,
          header: tHeader,
          merges,
          data,
          filename: this.filename,
          autoWidth: this.autoWidth,
          bookType: this.bookType,
        });
      });
    },
    formatJson(filterVal, jsonData) {
      return jsonData.map((v) =>
        filterVal.map((j) => {
          if (j === "timestamp") {
            return v[j];
          } else {
            return v[j];
          }
        })
      );
    },
  },
};
</script>

<style>
</style>

以上就是前端导出多表头的代码。

还有一点需要注意的是const merges = [“A1:A3”, “B1:F1”, “B2:B3”, “C1:F1”,“C2:F2”];

这是根据你表头在excel里面需要合并的行数和列数，根据自己的需求来写merges里面的数据，如果不懂得请看下面的效果图上的标注。

以上就是多级表头导出的代码和注意的点，若有不懂的地方欢迎来打扰。希望可以帮助到大家！