Merge pull request scratchfoundation#5088 from chrisgarrity/export-custom-mimetype

Get the mime-type for the file from the blob

Author: chrisgarrity

src/lib/download-blob.js

@@ -11,6 +11,7 @@ export default (filename, blob) => {
     const url = window.URL.createObjectURL(blob);
     downloadLink.href = url;
     downloadLink.download = filename;
+    downloadLink.type = blob.type;
     downloadLink.click();
     window.URL.revokeObjectURL(url);
     document.body.removeChild(downloadLink);