title: How to deal with missing file when adding N number of files to NodeJs Archiver
body: <p>I'm adding a series of files to zip using Archiver, but in the case that a file is missing, say if was deleted or moved, it obviously causes a problem. But I'm not able to get around this problem.</p>
  
  <p>My current code is like so:</p>
  
  <pre><code>for (var i=0; i&lt;receivedIds.length; i++) {
      var filePath = './public/pdf/letter-pdfs/'+receivedIds[i]+'.pdf';
      console.log(filePath);
      try {
          pdfStream = fs.createReadStream(filePath);
          archive.append(pdfStream, {name: receivedIds[i]+'.pdf'});
      } catch(e) {
          console.error(e);
      }
  }
  </code></pre>
  
  <p>Every time I try to wrap the append in a stream event like so:</p>
  
  <pre><code>pdfStream.on('readable', function() {
     archive.append(pdfStream, {name: receivedIds[i]+'.pdf'});
  });
  </code></pre>
  
  <p>The error is caught but the Archiver just outputs some empty file, even though some of the files do exist. How can I update this to append the files that do exist, and simply ignore the ones that don't?</p>