Is it possible to download an e-mail attachment, could be via Outlook or Imap, and send via http request only attachments that have a specific tag or string on it to a JavaScript application?
From there you would need to use IF or filter node to check for your tags/ string conditions (you may have to first convert your binary downloaded files; or turn them into n8n items so you can iterate over them if there are multiple attachments per email). Just depends on your specific usecase; but should be possible.
Recommend to get started with setting up the Email trigger - and let us know if you get stuck