Socket.on（）不执行

Question

I am trying to make a chat app with socket.io and I've run into a weird occurrence: my server receives the messages that I sent but the client doesn't.

Server Code:

var app = require('express')();
var http = require('http').createServer(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
    res.sendFile(__dirname + '\\index.html');
  });

  io.on('connection',function(socket){
    socket.on('chat message', function(msg){
      io.emit(msg)
      console.log('message: ' + msg)
    })
  })

http.listen(3002,function(){
    console.log('listening on 3002');
});

And here is the client's code:

<script>
      $(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){
          console.log(msg)
     // $('#messages').append($('<li>').text(msg));
      });
    });

</script>

where #m is am input field with the message I want to send

Answer 1

You have to emit an event name with some data :

From the docs :

socket.emit(eventName[, …args][, ack])

on the Server :

io.on('connection',function(socket){
    socket.on('chat message', function(msg){
      io.emit('newMessage', msg )  
//             ^^^^^^^^^^   ^^^^
//             event name   data

      console.log('message: ' + msg)
    })
  })

on the client :

socket.on('newMessage', function(msg){
      console.log(msg)
});