title: Extracting zipped files using JSZIP in javascript not working on IE11
body: <p>In my webpage, a user is supposed to upload a zipped file. Within the zipped file are multiple xlsx files. I am using below code for reading ZIP file , It works great on Chrome but when I am trying to run on IE11 it says, could not find resolve for null object or reference </p>
  
  <pre><code>    var JSZip = require('JSZip');
  fs.readFile{ filePath, function(err, data) {
    if (!err) {
      var zip = new JSZip();
      zip.loadAsync(data).then(function(contents) {
        Object.keys(contents.files).forEach(function(filename) {
          zip.file(filename).async('nodebuffer').then(function(content) {
             var dest = path + filename;
             fs.writeFileSync(dest, content);
          }); 
        });
      });
    }
  });
  </code></pre>
  
  <p>When I try to debug it is not going inside loadAync function.</p>