diff --git a/chat.js b/chat.js
index 59b86f8..154f9bc 100644
--- a/chat.js
+++ b/chat.js
@@ -1,190 +1,207 @@
-var app = require('express')();
-var http = require('http').Server(app);
-var io = require('socket.io')(http);
-var convert = require('color-convert');
+const app = require('express')();
+const http = require('http').Server(app);
+const io = require('socket.io')(http);
+const convert = require('color-convert');
 
 function randint(min, max) {
-    return min + Math.floor(Math.random() * (max-min));
+  return min + Math.floor(Math.random() * (max - min));
 }
 
 function randomColor() {
-    return '#'+convert.hsl.hex([randint(0,256), randint(50,200), randint(150,256)]);
+  return '#' + convert.hsl.hex([randint(0, 256), randint(50, 200), randint(150, 256)]);
 }
 
-function rgbToHex(r, g, b) {
-    return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
-}
-
-function usernameTaken(i, username) {
-    var keys = Object.keys(list);
-    var taken = false;
-    keys.forEach(function (iid) {
-        if (i !== iid && list[iid].name.toLowerCase() === username.toLowerCase())
-            taken = true;
-    });
-    return taken;
+function usernameTaken(list, username) {
+  return Object.values(list).filter(m => m.name.toLowerCase() === username.toLowerCase()).length > 0;
 }
 
 function escapeHtml(unsafe) {
-    return unsafe
-        .replace(/&/g, '&amp;')
-        .replace(/</g, '&lt;')
-        .replace(/>/g, '&gt;')
-        .replace(/"/g, '&quot;')
-        .replace(/'/g, '&#039;');
+  return unsafe
+    .replace(/&/g, '&amp;')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#039;');
+}
+
+function connectUser(list, socket) {
+  const iid = randint(0, 9999999);
+  const u = {
+    name: 'anonymous#' + ('0000' + randint(0, 9999)).slice(-4),
+    color: randomColor()
+  };
+  list[iid] = u;
+  console.log(u.name + ' connected');
+  socket.emit('chat message', {
+    color: '#fff',
+    name: '',
+    text: 'Welcome to the server'
+  });
+  setTimeout(function () {
+    socket.emit('new name', u.name);
+    socket.emit('new color', u.color);
+  }, 1000);
+  io.emit('chat message', {
+    color: '#fff',
+    name: '',
+    text: '<span style="color:' + u.color + '">' + escapeHtml(u.name) + '</span> connected.'
+  });
+  return iid;
+}
+
+function disconnectUser(list, iid) {
+  const u = list[iid];
+  if (!u)
+    return;
+  delete list[iid];
+  console.log(u.name + ' disconnected');
+  io.emit('chat message', {
+    color: '#fff',
+    name: '',
+    text: '<span style="color:' + u.color + '">' + escapeHtml(u.name) + '</span> disconnected.'
+  });
+}
+
+function userAction(list, iid, socket, msg) {
+  const u = list[iid];
+  if (!u) {
+    socket.emit('chat message', {
+      color: '#f00',
+      name: '',
+      text: 'You are not registered on the server'
+    });
+    return;
+  }
+  if (!msg.trim())
+    return;
+  console.log(u.name + '>' + msg);
+  if (msg[0] === '/') {
+    const arg1 = msg.split(' ')[1];
+    switch (msg.split(' ')[0]) {
+      case '/help':
+        socket.emit('chat message', {
+          color: '#fff',
+          name: '',
+          text: '' +
+            'List of commands :<br>' +
+            '<b>/color (color)</b> : change color (random if blank)<br>' +
+            '<b>/img [url]</b> : show image<br>' +
+            '<b>/list</b> : list users<br>' +
+            '<b>/me</b> : express yourself<br>' +
+            '<b>/nick [username]</b> : change username<br>'
+        });
+        break;
+      case '/color':
+        if (arg1 && /^#[0-9a-fA-F]{3,6}|[a-zA-Z-_]*$/.test(arg1)) {
+          u.color = arg1;
+        } else {
+          u.color = randomColor();
+        }
+        socket.emit('chat message', {
+          color: '#fff',
+          name: '',
+          text: 'Your new color is <span style="color:' + u.color + '">' + escapeHtml(u.color) + '</span>.'
+        });
+        socket.emit('new color', u.color);
+        break;
+      case '/img':
+        if (!arg1) {
+          socket.emit('chat message', {
+            color: '#f00',
+            name: '',
+            text: 'Please specify url'
+          });
+        } else {
+          io.emit('chat message', {
+            color: '#fff',
+            name: '',
+            text: '<span style="color:' + u.color + '">' + escapeHtml(u.name) + '</span><br><br>' +
+              '<img alt="' + encodeURI(arg1) + '" title="' + escapeHtml(arg1) + '" src="' + encodeURI(arg1) + '"/>'
+          });
+        }
+        break;
+      case '/list':
+        const keys = Object.keys(list);
+        let text = keys.length + ' users :';
+        keys.forEach(function (iid2) {
+          const m = list[iid2];
+          text += '<br>&gt;&nbsp;<span style="color:' + m.color + '">' + escapeHtml(m.name) + '</span>'
+        });
+        socket.emit('chat message', {
+          color: '#fff',
+          name: '',
+          text: text
+        });
+        break;
+      case '/nick':
+        let name = msg.trim().substr(msg.indexOf(' ') + 1);
+        if (name) {
+          name = name.substr(0, 200);
+          if (!usernameTaken(list, name)) {
+            let oldname = u.name;
+            u.name = name;
+            io.emit('chat message', {
+              color: '#fff',
+              name: '',
+              text: '<span style="color:' + socket.color + '">' + escapeHtml(oldname) + '</span> is now <span style="color:' + u.color + '">' + escapeHtml(u.name) + '</span>.'
+            });
+            socket.emit('new name', u.name);
+          } else {
+            socket.emit('chat message', {
+              color: '#f00',
+              name: '',
+              text: 'Username already taken'
+            });
+          }
+        } else {
+          socket.emit('chat message', {
+            color: '#f00',
+            name: '',
+            text: 'Please specify username'
+          });
+        }
+        break;
+      case '/me':
+        io.emit('chat message', {
+          color: u.color,
+          name: '',
+          text: '*<b>' + escapeHtml(u.name) + '</b> ' + escapeHtml(msg.trim().substr(msg.indexOf(' ') + 1)) + '*'
+        });
+        break;
+      default:
+        socket.emit('chat message', {
+          color: '#f00',
+          name: '',
+          text: 'Unknown command ' + msg.split(' ')[0] + '<br/>type /help for list of commands'
+        });
+        break;
+    }
+  } else {
+    io.emit('chat message', {
+      color: u.color,
+      name: u.name,
+      text: msg.substr(0, 2000)
+    });
+  }
 }
 
 app.get('/', function (req, res) {
-    res.sendFile(__dirname + '/chat.html');
+  res.sendFile(__dirname + '/chat.html');
 });
 
-var list = {};
+const list = {};
 
 io.on('connection', function (socket) {
-    socket.iid = randint(9999999);
-    socket.name = 'anonymous#' + ('0000' + randint(0,9999)).slice(-4);
-    socket.color = randomColor();
-    list['u'+socket.iid] = socket;
-    console.log(socket.name + ' connected');
-    socket.emit('chat message', {
-        color: '#fff',
-        name: '',
-        text: 'Welcome to the server'
-    });
-    setTimeout(function(){
-        socket.emit('new name', socket.name);
-        socket.emit('new color', socket.color);
-    },1000);
-    io.emit('chat message', {
-        color: '#fff',
-        name: '',
-        text: '<span style="color:' + socket.color + '">' + escapeHtml(socket.name) + '</span> connected.'
-    });
-    socket.on('disconnect', function () {
-        delete list['u'+socket.iid];
-        console.log(socket.name + ' disconnected');
-        io.emit('chat message', {
-            color: '#fff',
-            name: '',
-            text: '<span style="color:' + socket.color + '">' + escapeHtml(socket.name) + '</span> disconnected.'
-        });
-    });
-    socket.on('chat message', function (msg) {
-        if (!msg.trim())
-            return;
-        console.log(socket.name + '>' + msg);
-        if (msg[0] === '/') {
-            switch (msg.split(' ')[0]) {
-                case '/help':
-                    socket.emit('chat message', {
-                        color: '#fff',
-                        name: '',
-                        text: '' +
-                        'List of commands :<br>' +
-                        '<b>/color (color)</b> : change color (random if blank)<br>' +
-                        '<b>/img [url]</b> : show image<br>' +
-                        '<b>/list</b> : list users<br>' +
-                        '<b>/me</b> : express yourself<br>' +
-                        '<b>/nick [username]</b> : change username<br>'
-                    });
-                    break;
-                case '/color':
-                    var arg1 = msg.split(' ')[1];
-                    if (arg1 && /^#[0-9a-fA-F]{3,6}|[a-zA-Z-_]*$/.test(arg1)) {
-                        socket.color = arg1;
-                    } else {
-                        socket.color = randomColor();
-                    }
-                    socket.emit('chat message', {
-                        color: '#fff',
-                        name: '',
-                        text: 'Your new color is <span style="color:' + socket.color + '">' + escapeHtml(socket.color) + '</span>.'
-                    });
-                    socket.emit('new color', socket.color);
-                    break;
-                case '/img':
-                    var arg1 = msg.split(' ')[1];
-                    if(!arg1){
-                        socket.emit('chat message', {
-                            color: '#f00',
-                            name: '',
-                            text: 'Please specify url'
-                        });
-                    }else{
-                        io.emit('chat message', {
-                            color: '#fff',
-                            name: '',
-                            text: '<span style="color:' + socket.color + '">' + escapeHtml(socket.name) + '</span><br><br>' +
-                            '<img title="'+escapeHtml(arg1)+'" src="'+encodeURI(arg1)+'"/>'
-                        });
-                    }
-                    break;
-                case '/list':
-                    var keys = Object.keys(list);
-                    var text = keys.length + ' users :';
-                    keys.forEach(function (iid) {
-                        var m = list[iid];
-                        text += '<br>&gt;&nbsp;<span style="color:' + m.color + '">' + escapeHtml(m.name) + '</span>'
-                    });
-                    socket.emit('chat message', {
-                        color: '#fff',
-                        name: '',
-                        text: text
-                    });
-                    break;
-                case '/nick':
-                    var name = msg.trim().substr(msg.indexOf(' ') + 1);
-                    if (name) {
-                        name = name.substr(0,200);
-                        if (!usernameTaken(socket.iid, name)) {
-                            var oldname = socket.name;
-                            socket.name = name;
-                            io.emit('chat message', {
-                                color: '#fff',
-                                name: '',
-                                text: '<span style="color:' + socket.color + '">' + escapeHtml(oldname) + '</span> is now <span style="color:' + socket.color + '">' + escapeHtml(socket.name) + '</span>.'
-                            });
-                            socket.emit('new name', socket.name);
-                        } else {
-                            socket.emit('chat message', {
-                                color: '#f00',
-                                name: '',
-                                text: 'Username already taken'
-                            });
-                        }
-                    } else {
-                        socket.emit('chat message', {
-                            color: '#f00',
-                            name: '',
-                            text: 'Please specify username'
-                        });
-                    }
-                    break;
-                case '/me':
-                    io.emit('chat message', {
-                        color: socket.color,
-                        name: '',
-                        text: '*<b>' + escapeHtml(socket.name) + '</b> ' + escapeHtml(msg.trim().substr(msg.indexOf(' ') + 1)) + '*'
-                    });
-                    break;
-                default:
-                    socket.emit('chat message', {
-                        color: '#f00',
-                        name: '',
-                        text: 'Unknown command ' + msg.split(' ')[0] + '<br/>type /help for list of commands'
-                    });
-                    break;
-            }
-        } else {
-            io.emit('chat message', {
-                color: socket.color,
-                name: socket.name,
-                text: msg.substr(0,2000)
-            });
-        }
-    });
+  const iid = connectUser(list, socket);
+
+  socket.on('disconnect', function () {
+    disconnectUser(list, iid);
+  });
+  socket.on('chat message', function (msg) {
+    userAction(list, iid, socket, msg);
+  });
 });
 
 http.listen(3000, function () {
-    console.log('listening on *:3000');
+  console.log('listening on *:3000');
 });
\ No newline at end of file