Cheers

var message = msgpack.decode(new Uint8Array(event.data)); 

I'll try to debug that in the meantime.

I finally understood why this is happening, still don't know how to fix it though.

• As notepack.io has a browser-specific version for browsers specified on its package.json (see), it decodes the messages properly in the browser environment.
• When running inside Electron, it will load the Node.js version, not the browser one
• The colyseus.js client converts the incoming data to array via new Uint8Array(event.data), which can't be properly decoded in the Node.js version of the decoder.

Maybe you can fix this temporarily by replacing the lib/* files under node_modules/notepack.io with the ones located on browser/*. Of course this is not a definitive solution.

Thanks a lot for reporting and providing your example!