2👍
A few things. First I am going to assume that you are using the vue-cli webpack starter since you have a main.js and a .vue file.
You only need to use the socket.io middleware on the front end in your main.js. This will add a $socket property to all components that allows you to interact with the socket. You should remove the Vue.use(SocketIO) from Test.vue
Second, in main.js you have the connection set up as
Vue.use(VueSocketIO, 'http://localhost.com:8890');
when it should be
Vue.use(VueSocketIO, 'http://localhost:3000');
localhost.com is not your socket server. if your socket server is in dns or your host file it would be something like myserver.domain.com but since you are running the socket server and vue frontend on the same machine you can just use localhost or 127.0.0.1 (in most cases) as the server address
If you want to use port 8890, then you will need to change
server.listen(3000, function() {
to
server.listen(8890, function() {
in your server code.