sockjs

library0.3.24jsnpmunverified

SockJS-node is the server-side counterpart of SockJS-client, a browser library that provides a WebSocket-like API with cross-browser fallback transports. Current stable version is 0.3.24. It allows low-latency, full-duplex communication via WebSocket, polling, or streaming, compatible with older browsers. The project is in maintenance mode with infrequent updates; alternatives like WebSocket or Socket.IO may be preferred for new projects. Key differentiator: simple API, multiple transports, no build tools required.

messaging

npm install sockjs

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · SOCKJS

sockjs

messagingjavascriptv0.3.24

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

sockjs

✓ import * as sockjs from 'sockjs'

✗ const sockjs = require('sockjs')

Default import is not available; use namespace import or require. CommonJS require also works.

Server

✓ import { Server } from 'sockjs'

✗ import sockjs from 'sockjs'; const server = new sockjs.Server()

Named export for the Server class is available since v0.3.0. Also accessible via sockjs.createServer().

createServer

✓ import { createServer } from 'sockjs'

✗ import sockjs from 'sockjs'; const server = sockjs.createServer()

createServer is also a named export, but the default pattern is to use the default export as a factory function.

Creates a simple SockJS echo server that reflects messages back to the client over HTTP.

import http from 'http'; import { createServer } from 'sockjs'; const echo = createServer(); echo.on('connection', (conn) => { conn.on('data', (message) => { conn.write(message); }); conn.on('close', () => {}); }); const server = http.createServer(); echo.installHandlers(server, { prefix: '/echo' }); server.listen(9999, '0.0.0.0'); console.log('SockJS server running on port 9999');

Debug

Known issues

breakingSockJS-node v0.3.0 dropped support for Node < 0.10

fix

Upgrade to Node >= 0.10 or use sockjs@0.2.x

affects: >=0.3.0

deprecatedThe whole SockJS project is in maintenance mode; no active development

fix

Consider migrating to native WebSocket or a modern library like Socket.IO

affects: >=0

gotchaThe 'sockjs_url' option must be set to a valid URL for iframe transport security; default points to CDN, but may break if CDN is inaccessible

fix

Explicitly set sockjs_url to your hosted sockjs-client.min.js or a reliable CDN

affects: >=0

Errors

Common errors & fixes

Error: listen EADDRINUSE :::9999

Port already in use by another process

fix

Use a different port or kill the process occupying the port

TypeError: sockjs.createServer is not a function

Incorrect import method (e.g., using default import on v0.3.x)

fix

Use `import { createServer } from 'sockjs'` or `const sockjs = require('sockjs'); const server = sockjs.createServer();`

Upgrade

Version history

0.3.24latest on npm

Audit

Dependencies

faye-websocketrequiredUsed for WebSocket transport in the server

uuidrequiredGenerates unique session IDs

Agent activity

24 hits · last 30 days

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Resources

githubhttps://github.com/sockjs/sockjs-node ↗

packagesockjs ↗

homepagehttps://github.com/sockjs/sockjs-node ↗