Socket.io - Override text when user refresh page

I solve this problem a few hours but without result. What I need is when user is logged then everybody will see he is online. I have it already done but problem is when somebody refresh page. Then user is disconnected and connected back and the result is that I have a duplicity instead just update. Here is what I have on server side:

clients = [];

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

    if (socket.request.user.username in clients) {

        io.emit('chatMessage', {
            type: 'status',
            text: 'connected',
            created: Date.now(),
            username: socket.request.user.username,
            user_id: socket.request.user._id,
            socket_id: socket.id
        });


    } else {
        console.info('New client connected (id=' + socket.id + ').');
        // after connect set socket ID to username
        clients[socket.request.user.username] = socket.id;


    }

    socket.on('disconnect', function () {

        delete clients[socket.request.user.username];

    });
});

On the client side:

angular.module('messages')
    .controller('MessagesController', ['$scope', 'Socket', 'Authentication',
        function ($scope, Socket, Authentication) {

            $scope.authentication = Authentication;

            $scope.messages = [];
            Socket.on('chatMessage', function (message) {
                $scope.messages.push(message);
            });
        }
    ]);

And the view:

<section data-ng-controller="MessagesController">
                    <div data-ng-repeat="message in messages" data-ng-switch="message.type">
                        <strong data-ng-switch-when='status'>
                            <span data-ng-bind="message.created | date:'mediumTime'"></span>
                            <span data-ng-bind="message.username"></span>
                            <span>is</span>
                            <span data-ng-bind="message.text"></span>
                            <span data-ng-bind="message.user_id"></span>
                            <span>Socket.io ID is </span>
                            <span data-ng-bind="message.socket_id"></span>
                        </strong>
                    </div>
                </section>

And result is for example this:

12:08:38 AM jerry.klimcik is connected 5515ce05207842d412c07e03 Socket.io ID je URYiTSu4Zy0In2wNAAAL
12:27:30 AM admin is connected 55156119ec0b97ec217d8197 Socket.io ID is RcP_tyHarb5sN0XoAAAN
12:27:32 AM admin is connected 55156119ec0b97ec217d8197 Socket.io ID is 7dumGFZzgJunF49cAAAO

User admin refreshed page and now I see twice that he is logged. And I want to keep only his last connection. I'm really desperate.