WebSocket connection failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED
Chrome doesn't allow unsecure websocket (ws) connections to localhost (only wss, so you should setup a TLS certificate for your local web/websocket server).However the same should work fine with Firefox.
You need to use ws://yourIp:9090/, where yourIP is like 192.168.?.?.
try to change the port to 8080
const ws = new WebSocket('ws://localhost:8080/chat')