socket.io don't send data

I am making a chat, with user list.

I order to send user list on each user connexion i do the following action from the server :

io.on('connection', function (socket) {

    var users = [];

    socket.on('user connexion', function (username) {

        if (typeof users[socket.handshake.address] == "undefined" ) {
            users[socket.handshake.address] = [];
        }

        users[socket.handshake.address].push({username : username, color: "#"+((1<<24)*Math.random()|0).toString(16)});

        console.log(users);

        io.emit('user connexion',  {userlist : users});

    });

}

and in the front-end script i do :

socket.on('user connexion', function(userList){

    console.log(userList);
});

But the console display :

Object {userlist: Array[0]}

Any ideas ?