socket.io: io.origins is not a function

EDIT 2: As for why you're getting that CORS error, it's because you haven't configured the Socket.IO cors option properly.

Now, the cors configuration for Socket.IO actually gets passed to the NPM package cors, so you need to make your cors configuration work with the cors package.

For your case, that would look like:

cors: {
    // The `*` is used as the wildcard here.
    origin: "*",
    // Set the other options according to your needs.
    // The docs are here:
    // https://www.npmjs.com/package/cors#configuration-options
    methods: ["GET", "POST"],
    allowedHeaders: ["content-type"]
}

EDIT 1: Now that I know you are using Socket.IO 3.0, I may be able to help you better.

Socket.IO 3.0 includes a bunch of breaking changes (see the full changelog here), so that may be why you are getting that TypeError: io.origins is not a function.

As for that CORS error, Socket.IO 3.0 removed some old options, and added some new ones for CORS management. One of the removed options was the origins property. That's why your code is not working: you aren't actually setting any CORS configurations. To set CORS configurations in Socket.IO 3.0, use the options below:

// I still use a port here, because it works, but you could use @Aryas'
// code if you wish.
const io = socketIO(3000, {
  // Now, the CORS config.
  // You could either use the new `cors` property...
  cors: {
    origin: "https://example.com",
    methods: ["GET", "POST"],
    allowedHeaders: ["content-type"]
  },
  // ...Or the old `allowRequest` function.
  allowRequest: function(req, callback) {
    callback(null, req.headers.referer.startsWith("https://example.com"));
  }
});

Oh, and, setting CORS options in Express is not necessary; Socket.IO picks up requests that are for it automatically, before any Express handlers are called.

ORIGINAL ANSWER:
It's telling you that because your io variable is not an instance of the Socket.IO server. Instead, it's the Socket.IO server constructor. Why?

Well, you have this code:

// You are passing two parameters to `require`: "socket.io", and 3000
var io = require("socket.io", 3000);

require returns whatever is exported by the module, which, in this case, is the Socket.IO server constructor (not an instance of it). The 3000 you passed to require doesn't do anything, since require only accepts one argument.

In order to get a Socket.IO server instance, you need to do this:

// The clearer way:
// `socketIO` is the Socket.IO server constructor.
var socketIO = require("socket.io");
// `io` is the Socket.IO server instance.
var io = socketIO(3000);

// The shorter way:
// Calling the result of `require` (the Socket.IO server constructor) as a function.
var io = require("socket.io")(3000);

UPDATE 2

As you mentioned in this https://pastebin.com/1TDhWxaC code I found that you are using fire fox try this code on Chrome or other browser's i think it will work on that browser

There is bug or problem certificate or something else in in firefox you will notice this in all below cases

I suggest you to go through below questions and answers

1. Firefox 'Cross-Origin Request Blocked' despite headers
2. CORS request did not succeed on Firefox but works on Chrome
3. Socket.io + Node.js Cross-Origin Request Blocked
4. CORS Blocked with node.js and socket.io
5. Socket.IO: Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource

//Error in Firefox client: //Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://<MY_EXTERNAL_IP>:3000/socket.io/?EIO=3&//transport=polling&t=NMX8aWc. (Reason: CORS request did not succeed)

UPDATE 1 IN your app.js or index.js put below code

app.use(function (req, res, next) {
  res.header("Access-Control-Allow-Origin", '*');
  res.header("Access-Control-Allow-Credentials", true);
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
  res.header("Access-Control-Allow-Headers", 'Origin,X-Requested-With,Content-Type,Accept,content-type,application/json');
  res.header("Cache-Control", "no-store, no-cache, must-revalidate, proxy-revalidate, max-age=0");
  next();
});

If you are using firefox refer to this answer : Answer on stackOverflow

And Install cors If you haven't used in your app

You can use cors npm in express.

npm install cors

Update app.js

var express = require('express')
var cors = require('cors')
var app = express()

app.use(cors())

ORIGINAL ANSWER Try This maybe it could Work for you it is working fine in my app

var express = require('express');
var app = express();
var http = require('http').Server(app);
const io = require('socket.io')(http, {
  origins: '*:*'
});

http.listen(port);
console.log('Server is running on port:' + port);