<form action="" [formGroup]="messageForm" (ngSubmit)="sendMessage()">
  <input id="message" formControlName="message" #message class="form-control" class="messageInput" autocomplete="off"/>
  <button type="submit" class="btn btn-primary btn-lg btn-block">SEND</button>
</form>

sendMessage() {
  if (this.messageForm.valid) {
    this.message = this.messageForm.get('message').value;
    this.messageForm.reset();
    this.socket.emit('chat message', this.message);
    this.socket.on('chat message', this.receive);
  }
}

receive = function(msg) {
  console.log('receive called');
  const li = document.createElement('li');
  document.getElementById('messageList').appendChild(li);
  li.innerHTML = msg;
};

io.on('connection', function(socket){
    socket.on('disconnect', function(){
    });
   socket.on('chat message', function(msg){
        io.emit('chat message', msg);
   });
 });

$(function () {
    var socket = io();
    $('form').submit(function(e){
        e.preventDefault(); // prevents page reloading
        socket.emit('chat message', $('#m').val());
        $('#m').val('');
         return false;
    });
    socket.on('chat message', function(msg){
        $('#messages').append($('<li>').text(msg));
    });
});