People could then use netcat to send and receive, and the server could block either end until someone connects on the other end. Personally I would really appreciate a tool I could connect to with netcat or anything else that speaks TCP. I don’t know how someone would use the service from javascript though.
No buffering needed by the server. If either end has to be asynchronous, just run in background + nohup if you’re calling this from a shell.
Maybe some inspiration from how blocking FIFOs work on Linux: http://man7.org/linux/man-pages/man7/fifo.7.html
You could even do a non-blocking version which just refuses connection. netcat can be set to retry: https://unix.stackexchange.com/questions/432249/nc-to-retry-...
I realise that this doesn’t make it easy to indicate which pipe one wants to connect to.