I am trying to build a bus application which shall behave exactly like this (<http://pdxlivebus.com/>) one.

Now I simply can not get the idea out that how can i constantly feed data to the UI from my backend? I don't want to send ajax requests after some intervals. I have done chat application with react and node.js but they are realtime in a sense that one user does something(send message or disconnect) and for that the server sends out a socket event and the client listens and updates.

But application like this one <http://pdxlivebus.com/> where the user does not do anything but to watch the buses how does the UI gets updated with the latest data?