title: Multiple blobs to single zip file with JSzip?
body: <p>i try to download multiple images with single ZIP  file but i get the opposite. Which is to download zip files but they come in separated zip files .
  And when i console log the <code>urls[]</code> array they come in different arrays .</p>
  <pre class="lang-js prettyprint-override"><code>const fileURLs = window.URL.createObjectURL(result);// that is blob 
  var zip = new JSZip();
  var count = 0;
  var zipFilename = &quot;Selective.zip&quot;;
  var urls = [ // i try to make them array 
  fileURLs 
  ];
  
  console.log(urls);
  
    urls.forEach(function(url){
    var filename = result.name;
    // loading a file and add it in a zip file
    JSZipUtils.getBinaryContent(url, function (err, data) {
       if(err) {
          throw err; // or handle the error
       }
       zip.file(filename, data, {binary:true});
       count++;
         zip.generateAsync({type:'blob'}).then(function(content) {
            saveAs(content, zipFilename);
         });
  
    });
  });
  </code></pre>