title: ExcelJS - Strict-mode does not allow assignment to undefined variables: regeneratorRuntime
body: <p>I'm using DevExtreme dxDataGrid and I want to export data to an xlsx-file. They have implemented it using ExcelJs:
  <a href="https://js.devexpress.com/Documentation/ApiReference/Common/Utils/excelExporter/#exportDataGridoptions" rel="nofollow noreferrer">https://js.devexpress.com/Documentation/ApiReference/Common/Utils/excelExporter/#exportDataGridoptions</a></p>
  <p>As explained I just need to reference the following libs:</p>
  <pre><code>&lt;head&gt;
          &lt;!-- ... --&gt;
          &lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/babel-polyfill/7.4.0/polyfill.min.js&quot;&gt;&lt;/script&gt;
          &lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/exceljs/4.1.1/exceljs.min.js&quot;&gt;&lt;/script&gt;
          &lt;script src=&quot;https://cdnjs.cloudflare.com/ajax/libs/FileSaver.js/2.0.2/FileSaver.min.js&quot;&gt;&lt;/script&gt;
          &lt;!-- reference the DevExtreme sources here --&gt;
  &lt;/head&gt;
  </code></pre>
  <p>I'm using ASP.NET Core 6 with VS 2022. For this I'm using the <a href="https://marketplace.visualstudio.com/items?itemName=MadsKristensen.BundlerMinifier" rel="nofollow noreferrer">Bundler &amp; Minifier</a> to bundle libs like jQuery, DevExtreme and ExcelJs.</p>
  <p>I have downloaded ExcelJs (like I have done for jQuery etc.) with libman.json:</p>
  <pre><code>{
    &quot;version&quot;: &quot;1.0&quot;,
    &quot;defaultProvider&quot;: &quot;cdnjs&quot;,
    &quot;libraries&quot;: [
      {
        &quot;library&quot;: &quot;jquery@3.6.0&quot;,
        &quot;destination&quot;: &quot;wwwroot/js/lib/jquery/&quot;
      },
      {
        &quot;provider&quot;: &quot;cdnjs&quot;,
        &quot;library&quot;: &quot;exceljs@4.3.0&quot;,
        &quot;destination&quot;: &quot;wwwroot/js/lib/exceljs/&quot;,
        &quot;files&quot;: [
          &quot;exceljs.min.js&quot;,
          &quot;exceljs.js&quot;
        ]
      },
      {
        &quot;provider&quot;: &quot;cdnjs&quot;,
        &quot;library&quot;: &quot;FileSaver.js@2.0.5&quot;,
        &quot;destination&quot;: &quot;wwwroot/js/lib/FileSaver.js/&quot;
      },
      {
        &quot;provider&quot;: &quot;cdnjs&quot;,
        &quot;library&quot;: &quot;babel-polyfill@6.26.0&quot;,
        &quot;destination&quot;: &quot;wwwroot/js/lib/babel-polyfill/&quot;
      }
    ]
  }
  </code></pre>
  <p>Then I have added ExcelJs to my bundleconfig.json:</p>
  <pre><code>[
    {
      &quot;outputFileName&quot;: &quot;wwwroot/bundle/LibraryBundle.js&quot;,
      &quot;inputFiles&quot;: [
        &quot;wwwroot/js/lib/jquery/jquery.js&quot;,
        &quot;wwwroot/js/lib/babel-polyfill/polyfill.js&quot;,
        &quot;wwwroot/js/lib/exceljs/exceljs.js&quot;,
        &quot;wwwroot/js/lib/FileSaver.js/FileSaver.js&quot;
  
      ]
    }
  ]
  </code></pre>
  <p>Then I'm getting following error in Visual Studio:</p>
  <blockquote>
  <p>Strict-mode does not allow assignment to undefined variables: regeneratorRuntime</p>
  </blockquote>
  <p><code>strict-mode</code> is defined in ExcelJS and also many other lib's I don't understand why I'm getting this error and how can I fix it. I was not able to find any similar issue at Github-ExcelJs and it doesn't look like that they are not really supporting their open issues. Because of that I'm tried to ask here.</p>