Use of 3rd Party Javascript modules?

Not via the online Editor. If you would like to use node_modules, you would have to generate the code offline and upload the built JS code to the online Editor. GitHub - playcanvas/playcanvas-sync: Real-time synchronization of files between PlayCanvas and your local machine can help with getting a workflow set up for this.

If you want a whole PlayCanvas project into a Vue/Node app (e.g like a configurator, that’s where it gets a bit tricky)

@iso74 has done something similar here: PlayCanvas and Vue.js

I’m a little unclear on how you would like to use node_modules at the moment.