title: 'ReferenceError: cptable is not defined' when running Jest tests, the actual code to generate the excel sheet works fine
body: <p>The stack trace is as follows.</p>
  <pre><code>Test suite failed to run
  
  ReferenceError: cptable is not defined
  
    1 | import React, { Component } from 'react';
  &gt; 2 | import ReactExport from 'react-export-excel';
      | ^
  
    at cptable (node_modules/react-export-excel/node_modules/xlsx/xlsx.js:10:37)
    at Object.&lt;anonymous&gt; (node_modules/react-export-excel/node_modules/xlsx/xlsx.js:6:1)
    at Object.require (node_modules/react-export-excel/dist/ExcelPlugin/components/ExcelFile.js:19:13)
    at Object.require (node_modules/react-export-excel/dist/index.js:7:18)
    at Object.&lt;anonymous&gt; (components/CustomReport.jsx:2:1)
  </code></pre>
  <p>If i follow the trace, it reaches the following code section</p>
  <p>at cptable (node_modules/react-export-excel/node_modules/xlsx/xlsx.js:10:37)</p>
  <pre><code>if(typeof cptable === 'undefined') cptable = require('./dist/cpexcel');
  </code></pre>
  <p>I've seen github issues where they suggest to remove &quot;use strict&quot; from component code but I'm not even using it. Here is the related issue <a href="https://github.com/SheetJS/sheetjs/issues/324" rel="nofollow noreferrer">https://github.com/SheetJS/sheetjs/issues/324</a></p>