In the past I've been hit it's the "non exe" permission and for a while you were able to bypass it by putting it in an archive file (Always found emailing myself files handy when I didn't have a thumb drive to hand), but they scan the file types of the files inside of archives these days so emailing a zip with a exe in it doesn't work.

I guess the same will apply for .js files which might be a pain when emailing a client a zip of the programming work you have done for them, but they do say you can use Google Drive to host the file and send them a link to the google drive download.