Socket.io : “Cannot read property 'emit' of undefined”

问题

So I'm currently developping my website using socket.io.

Today, while I was implementing the sockets, I got a nice little error "Cannot read property 'emit' of undefined" I can not find what's wrong in my code so I hope you guys can help me.

App.js:

var socket  = require( 'socket.io' );
var express = require('express');
var app     = express();
var server  = require('http').createServer(app);
var io      = socket.listen( server );
var port    = 9999;

server.listen(port, function () {
  console.log('Listening at port %d', port);
});

io.sockets.on('connection', function (socket) {
    console.log('User connected');

    socket.on('create_socket', function(port){
    console.log(port);
});

Client Side:

<div>
    <p class="connected" hidden>Connected port : 9999</p>
    <p class="connect_error" hidden><strong>Can not connect to socket on port 9999</strong></p>
</div>

<script>
    var socket = io.connect("http://localhost:9999");

    // If connection can not be established
    socket.on('connect_error', function(socket) {
        $('.connected').hide();
        $('.connect_error').show();
    });

    // Connection established
    socket.on('connect', function(socket) {
        $('.connect_error').hide();
        $('.connected').show();
       // socket.on('create_socket', null, <?= $port; ?> );
       socket.emit('create_socket', '<?= $port; ?>');
    });
</script>

Btw, all the socket.io/jquery/... includes are done correctly even if they doesn't appear on the code

Thanks in advance

回答1:

Client Code:

Change

// Connection established
    socket.on('connect', function(socket) {

// Connection established
    socket.on('connect', function(data) {

final:

// Connection established
    socket.on('connect', function(data) {
        $('.connect_error').hide();
        $('.connected').show();
       console.log(data);
       socket.emit('create_socket', '<?= $port; ?>');
    });

Previously, you where overwriting the socket object.

来源：https://stackoverflow.com/questions/37725948/socket-io-cannot-read-property-emit-of-undefined

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jquery

node.js

sockets

Socket.IO