TCP echo server for Node.js

README.md

TCP echo server for Node.js

Usage

1. Make sure you have a modern-ish version of Node.js installed.
2. Type npx https://gist.github.com/kfox/1280c2f0ee8324067dba15300e0f2fd3
3. Connect to it from a client, e.g. netcat or similar: nc localhost 9000

echo.mjs

#!/usr/bin/env node

import net from 'node:net'

const port = process.argv[2] || 9000

const server = net.createServer((connection) => {
  const { address, port } = connection.address()
  const socket = `${address}:${port}`

  console.log(`${socket} - client connected`)

  connection.on('data', (data) => {
    console.log(`${socket} - client sent: %s`, String(data).trim())
    connection.write(data)
  })

  connection.on('end', () => {
    console.log(`${socket} - client disconnected`)
  })
})

server.listen({ port }, () => {
  const { address, port } = server.address()
  console.log('listening on %s:%d', address, port)
})

package.json

{
  "name": "tcp-echo-server",
  "version": "1.0.0",
  "bin": "./echo.mjs"
}