Download blob from ajax request.
<ajax-blob-downloader
id="downloader"
default-file-name="checklist.txt">
</ajax-blob-downloader>`<iron-ajax
id="downloadAjax"
handle-as="blob"
loading="{{_downloading}}"
on-response="_onFileDownloaded"
on-error="_onFileFailed">
</iron-ajax> _onFileDownloaded(e) {
this.$.downloader.download(e.detail);
}