socket with vuex not work

[Caraws]

On Server

io.on('connection', function(socket){
  console.log('a user connected');
  socket.on('disconnect', function(){
      console.log('user disconnected');
  });

  socket.emit("SOCKET_USER_MESSAGE",'hi');

  socket.on('emit_method', function(data){
      console.log(data);
  });
});

On Vuex

SOCKET_CONNECT : (state,status) => {
		state.connect = true;
		alert('connect with socket.io')
	},
	SOCKET_USER_MESSAGE : (state,message) => {
		alert(message)
		state.newMessage = message
	}

connect is success, but i can't get message.

And in this way,it's work

sockets: {
            SOCKET_USER_MESSAGE : function (data) {
                console.log(data)
            }
        }

What did I do wrong ??

[MetinSeylan]

io.on('connection', function(socket){
  console.log('a user connected');
  socket.on('disconnect', function(){
      console.log('user disconnected');
  });

  socket.emit("USER_MESSAGE",'hi'); // "SOCKET_" prefix is only client side

// or   socket.emit("user_message",'hi');

  socket.on('emit_method', function(data){
      console.log(data);
  });
});

[Caraws]

thx!! it's work~

[Caraws]

i have other question...
in IE11
[Vue warn]: Error in beforeCreate hook: (found in <xxx>)
only on IE11