var net = require('net');var count = 0,  users = {};var server = net.createServer(function (conn) {  console.log('连接到');  conn.write(     "/r/n > welcome to node-chat!"    + "/r/n > " + count + " other people are connected at this time."    + "/r/n > please write your name and press enter: "   );  count++;  // 代表当前连接的昵称  var nickname;  console.log(conn);  conn.on('data', function (data) {    // 删除/r/n    // data = data.replace('/r/n', '  ');    // 当前注册的昵称不存在    if (!nickname) {      // 用户名存在      if(users[data]) {        conn.write('nickname in use');        return;      } else {        // 用户名给nickname        nickname = data;        users[nickname] = conn;        for (var i in users) {          users[i].write('/r/n > ' + nickname + ' join our room /r/n > I: ');        }      }    } else {      // 开始聊天      for (var i in users) {        if (i != nickname) {          users[i].write('/r/n > ' + nickname + ': ' + data);        }      }    }   });  conn.on('close', function () {    count--;  });  conn.setEncoding('utf8');});server.listen(3000, function () {  console.log('服务器监听端口3000');})