xpublish | Publish Xarray Datasets via a REST API | REST library

_{In case one has never worked with ZeroMQ,
one may here enjoy to first look at "ZeroMQ: Principles in less than Five Seconds"
before
diving into further details}

Q : "Is there a way to call setSockOpt() with zeromq.js or is there another way to accept a subscription?"

So, let me first mention Somdoron to be, out of doubts & for ages, a master of the ZeroMQ tooling.

Next comes the issue. The GitHub-sources, I was able to review atm, seem to me, that permit the ZMQ_XPUB-Socket-archetypes to process the native API ZMQ_XPUB_MANUAL settings ( re-dressed into manual-property, an idiomatic shift ), yet present no method (so far visible for me) to actually permit user to meet the native API explicit protocol of:

ZMQ_XPUB_MANUAL: change the subscription handling to manual
...
with manual mode subscription requests are not added to the subscription list. To add subscription the user need to call setsockopt() with ZMQ_SUBSCRIBE on XPUB socket.
_{/__ from ZeroMQ native API v.4.3.2 documentation __/}

Trying to blind-call the Socket-inherited .SetSockOpt() method may prove me wrong, yet if successfull, it may be a way to inject the { ZMQ_SUBSCRIBE | ZMQ_UNSUBSCRIBE } subscription-management steps into the XPUB-instance currently having been switched into the ZMQ_XPUB_MANUAL-mode.

Please test it, and if it fails to work via this super-class inherited method, the shortest remedy would be to claim that collision/conceptual-shortcommings directly to the zeromq.js maintainers ( it might be a W.I.P. item, deeper in their actual v6+ refactoring backlog, so my fingers are crossed for either case & my full respect for their brave work ).