我的聊天应用程序遇到问题，我需要能够向特定用户发送私人消息，我可以选择该特定用户，但由于某些原因无法弄清楚如何发送私人消息。

在下面，您将找到我服务器的代码，请提供帮助：

var express = require('express');

var app = express();

var PORT = process.env.PORT || 8000;

var http = require('http').Server(app); // this is a node server that uses express as the boiler plate

var io = require('socket.io')(http); // socket! pass our server as a parameter to it





// use express static to expose a folder

app.use(express.static(__dirname + '/public'));



var users = [],

    connections = [];

var onlineClients = {};









// Register events on socket connection

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

    connections.push(socket);

    // console.log("connected socket", connections);



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

        users.splice(users.indexOf(socket.username), 1);

        updateUsernames();

        connections.splice(connections.indexOf(socket), 1);

        console.log("disconnected socket", connections.length)

    });



    socket.on("send message", function(data) {

        // console.log(data);

        io.emit("new message", {msg: data, user: socket.username});

    });





    socket.on("notify user", function(data) {

        io.emit("notify user", {user: socket.username})

    });





    socket.on("new user", function(data) {

        socket.username = data;

        users.push(socket.username);

        updateUsernames();



    });



    function updateUsernames() {

        io.emit("get users", users);

    };



    socket.on("private", function(data, recipientName) {

        var recipient = connections.filter(function (recipient) {

            return recipient.username === recipientName;

        })[0];

            console.log(recipient.id);

            console.log(data);

        io.sockets.socket(recipient.id).emit("received private msg", data);



    });





    // socket.on("create room", function(room) {

    //  socket.join(room);

    //  io.sockets.in(room).emit('event', "hey wusup am in this room");

    //  console.log(socket);



    // })



});



http.listen(PORT, function(){

  console.log('Server started on port ' + PORT);

});