Cannot read property 'el' of undefined

[dw08]

Cannot read property 'el' of undefined
at Table2Excel.toSheet (table2excel.js?3378:161)
at eval (table2excel.js?3378:104)
at Array.forEach ()
at Table2Excel.toExcel (table2excel.js?3378:98)
at Table2Excel._export (table2excel.js?3378:199)
at VueComponent.exportTest (StatisticsView.vue?e8d4:313)
at VueComponent.invoker (vue.esm.js?65d7:2027)
at VueComponent.Vue.$emit (vue.esm.js?65d7:2538)
at VueComponent.handleClick (iview.js?5654:10403)
at invoker (vue.esm.js?65d7:2027)

table code:
<table border="1" class="test"> <thead> <tr style="text-align: right;"> <th></th> <th></th> <th>过货票数(排重)</th> <th>过货次数</th> <th>开包率</th> <th>过货件数(实际)</th> <th>过货时长</th> <th>图片数</th> <th>开包次数</th> <th>测试</th> </tr> <tr> <th>通道</th> <th>货物类型名</th> <th></th> <th></th> <th></th> <th></th> <th></th> <th></th> <th></th> <th></th> </tr> </thead> <tbody> <tr> <th>C仓通道1</th> <th>超大超重货物</th> <td>1</td> <td>1</td> <td>0%</td> <td>23</td> <td>15.0</td> <td>0.0</td> <td>0.0</td> <td>test</td> </tr> <tr> <th rowspan="4" valign="top">C仓通道3</th> <th>危险品货物</th> <td>4</td> <td>5</td> <td>22%</td> <td>12</td> <td>62.0</td> <td>0.0</td> <td>22.0</td> <td>test</td> </tr> <tr> <th>快件货物</th> <td>2</td> <td>2</td> <td>0.32%</td> <td>2</td> <td>0.0</td> <td>19.0</td> <td>6.0</td> <td>test</td> </tr> <tr> <th>超大超重货物</th> <td>2</td> <td>2</td> <td>1.78%</td> <td>17</td> <td>3.0</td> <td>9.0</td> <td>16.0</td> <td>test</td> </tr> <tr> <th>邮件货物</th> <td>7</td> <td>11</td> <td>30%</td> <td>356</td> <td>5618.0</td> <td>0.0</td> <td>30.0</td> <td>test</td> </tr> <tr> <th rowspan="5" valign="top">测试通道1</th> <th>危险品货物</th> <td>13</td> <td>22</td> <td>0.03%</td> <td>22222220000</td> <td>1483.0</td> <td>1353.0</td> <td>44.0</td> <td>test</td> </tr> <tr> <th>快件货物</th> <td>5</td> <td>17</td> <td>0.01%</td> <td>194</td> <td>2997.0</td> <td>2129.0</td> <td>28.0</td> <td>test</td> </tr> <tr> <th>普通货物</th> <td>21</td> <td>46</td> <td>0.02%</td> <td>1013</td> <td>539.0</td> <td>3941.0</td> <td>78.0</td> <td>test</td> </tr> <tr> <th>超大超重货物</th> <td>10</td> <td>34</td> <td>0.03%</td> <td>175</td> <td>191.0</td> <td>1485.0</td> <td>44.0</td> <td>test</td> </tr> <tr> <th>邮件货物</th> <td>29</td> <td>70</td> <td>0.03%</td> <td>2925</td> <td>4926.0</td> <td>4867.0</td> <td>147.0</td> <td>test</td> </tr> <tr> <th>快件货物</th> <td>3</td> <td>9</td> <td>27%</td> <td>58</td> <td>210.0</td> <td>1.0</td> <td>27.0</td> <td>test</td> </tr> <tr> <th>普通货物</th> <td>6</td> <td>18</td> <td>0.67%</td> <td>126</td> <td>1166.0</td> <td>6.0</td> <td>4.0</td> <td>test</td> </tr> <tr> <th>超大超重货物</th> <td>4</td> <td>15</td> <td>0%</td> <td>59</td> <td>868.0</td> <td>78.0</td> <td>0.0</td> <td>test</td> </tr> <tr> <th>邮件货物</th> <td>10</td> <td>47</td> <td>0.01%</td> <td>3480</td> <td>207.0</td> <td>1413.0</td> <td>14.0</td> <td>test</td> </tr> <tr> <th>超大超重A区</th> <th>邮件货物</th> <td>1</td> <td>1</td> <td>0%</td> <td>0</td> <td>15.0</td> <td>0.0</td> <td>0.0</td> <td>test</td> </tr> <tr> <th>All</th> <th></th> <td>120</td> <td>302</td> <td>82%</td> <td>22222230000</td> <td>18300.0</td> <td>15311.0</td> <td>461.0</td> <td>test</td> </tr> </tbody> </table>

[JackGit]

how do you use it in your code, please show me more details