vue 專案中 實現列表的匯出excel表格的功能

vue在做後臺管理系統，會有匯出excel表格的功能。

首先，通過npm或者yarn安裝外掛xlsx和file-saver

npm i xlsl -S // 用於匯出Excel表
npm i file-saver -S // 用於檔案的下載

然後，話不多說複製就完事了，建立一個js檔案ExportExcel.js,將下面所有程式碼ctrl + c，ctrl + v 到裡面。這段程式碼為封裝的匯出表格的功能。

/* eslint-disable */
require('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({
  header,
  data,
  filename,
  autoWidth = true,
  bookType=  'xlsx'
} = {}) {
  /* original data */
  filename = filename || 'excel-list'
  data = [...data]
  data.unshift(header);
  var ws_name = "SheetJS";
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

  if (autoWidth) {
    /*設定worksheet每列的最大寬度*/
    const colWidth = data.map(row => row.map(val => {
      /*先判斷是否為null/undefined*/
      if (val === null) {
        return {
          'wch': 10
        };
      }
      /*再判斷是否為中文*/
      else if (val.toString().charCodeAt(0) > 255) {
        return {
          'wch': val.toString().length * 2
        };
      } else {
        return {
          'wch': val.toString().length
        };
      }
    }))
    /*以第一行為初始值*/
    let result = colWidth[0];
    for (let i = 1; i < colWidth.length; i++) {
      for (let j = 0; j < colWidth[i].length; j++) {
        if(result[j]!=undefined){
          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}`);
}

生成表格的程式碼如下寫在vue的methods裡面（別告訴我你不知道methods），下面程式碼有詳細註釋，如果看不懂就複製到methods裡面看效果，然後一點點的改就ok了,需要修改五個地方。

首先，列表中資料我是放在放在dataList陣列中了，第一行dataList需要改
其次，第二行的import()裡面的路徑需要修改，路徑為你上面新建的ExportExcel.js的路徑
其次，tHeader陣列裡面的標題可以修改。根據需要改，不限制個數。
然後，filterVal陣列裡面的值為資料的欄位，就是dataList陣列中物件的屬性,需要修改。
最後，第20行的filename的值為檔名，可以修改。

exportExcel() {
      const sourceOriginAmount = this.dataList
      import('@/components/ExportExcel/Export2Excel.js').then(excel => { // 匯入js模組
        const tHeader = ['首次預警時間', '最近預警時間', '轄區', '經緯度', '報警來源', '報警頻次'] // 匯出excel 的標題
        const filterVal = ['firstDatetime', 'nearDateTime', 'Address', 'LatitudeLongitude', 'Alarmresource', 'observationFrequency'] // 每個標題對應的欄位
        const list = (sourceOriginAmount || []).map((item, key) => { // 通過 map 方法遍歷，組裝資料成上面的格式
          return {
            firstDatetime: item.observationDatetime.replace('T', ' ').substring(5, 16),
            nearDateTime: '',
            Address: item.formattedAddress,
            LatitudeLongitude: Math.ceil(item.longitude) + ',' + Math.ceil(item.latitude),
            Alarmresource: '衛星',
            observationFrequency: item.observationFrequency
          }
        })
        if (list) {
          const data = this.formatJson(filterVal, list) // 生成json資料
          excel.export_json_to_excel({ // 呼叫excel方法生成表格
            header: tHeader,
            data,
            filename: '報警管理'
          })
        } else {
          alert('暫無資料')
        }
      })
    },
    formatJson(filterVal, jsonData) {
      return jsonData.map(v => filterVal.map(j => v[j]))
    }

如果不成功，請看是不是複製全了，或者單詞寫錯了，重灌一下開始的外掛，如果成功了，贊一個吧