This is the skeleton of a presentation using reveal.js and socket.io, allowing you to use your web browser to give a presentation controlled from any other device (smartphone).
See the demo for reveal.js here and the github repo here.
Do npm install then npm start.
You need node/nodemon and npm.
You can see the barebones HTML presentation at localhost/8080, and the controller at localhost/8080/controller. Pushing buttons on a controller open in any window will affect presentations in any other window as long as they are all connected to the same server.
Spectacle now has this feature built in. If you like React, use that instead of an ugly amateur hack like this.