The data has been updated on the server. How to inform the client?

Question

Node.js

When loading a page, I request a list of users from the server (get ajax) and display it. Let's say a new user has been added (added by another client). How to inform all clients that they need to make a request again (update data)?
At the office The React site in the Tutorial requests data from the server every 2 seconds, but I don't think this is the best option.
setInterval(this.loadCommentsFromServer, 2000);

Answer 1

web socket