In develop
<script>
var exportText; // this variable needs to contain your content
var targetFilename = "myfilename.ext"

function presentExportFile() {
  var download = document.createElement('a');
  // you need to change the contenttype to your needs in the next line.
  download.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(exportText));
  download.setAttribute('download', targetFilename);

  download.style.display = 'none';
  document.body.appendChild(download);

  download.click();

  document.body.removeChild(download);
}
</script>