Hey Ague – If i am understanding your problem correctly you can actually use the pubsub system to get an update when the user goes live. This little package sets everything up for you fairly well.
The docs are pretty bad, but if you have any questions about it I can probably help you.
Simply subscribe to whatever channels you want to follow:
(You can listen to new channels too without having to restart the node program)
// Change Bajheera to whatever channel you want to listen too
var realtime = new Realtime({defaultTopics:[“video-playback.bajheera”]});
realtime.on(‘bits’, (data) => {
// Do something with the data
});