Very nice addon.
I’m just suggesting an edit to process the files in batches. It looks like it converts the entire file to entities before they are imported (at the preview stage). I would suggest loading only the first say 10x lines of the file to entities at the preview stage then processing the rest of the file in batches.
Unless it already does it… But I am getting a heap-space error when I try and upload only a few thousand entities. The files I was hoping to upload contain in excess of 500k separate lines.
Anyways, just a suggestion. 