joinRoom

.js

function joinRoom(socket, room) {
    socket.join(room);
    currentRoom[socket.id] = room;
    socket.emit('joinResult', {room: room});
    socket.broadcast.to(room).emit('message', {text: nickNames[socket.id] + 'has joined ' + room + '.'});
    var usersInRoom = io.sockets.clients(room);
    if (usersInRoom.length > 1) {
        var usersInRoomSummary = 'Users currently in ' + room + ': ';
        for (var index in usersInRoom) {
            var userSocketId = usersInRoom[index].id;
            if (userSocketId != socket.id) {
                if (index > 0) {
                    usersInRoomSummary += ', ';
                }
                usersInRoomSummary += nickNames[userSocketId];
            }
        }
        usersInRoomSummary += '.';
        socket.emit('message', {text: usersInRoomSummary});
    }
}