Consuming data isn't hard. Creating a dashboard that displays the values sent down on an interval over a websocket is super easy.

Sending data isn't hard. Sending the mouse coordinates on a click to the server over a websocket is super easy.

There is, however, no easy way to consume data and send a response. To write an echo server, for example, you currently have to send the data to a javascript port and then read from the port to send it back.