on-net-listen

Observe when something in your node app starts listening on a TCP port.

npm install on-net-listen

Uses async_hooks behind the scenes and requires Node >=9

Usage

var onnetlisten = require('on-net-listen')
 
onnetlisten(function (addr) {
  // addr is the same object as server.address()
  // for the port do addr.port
  console.log('Someone started listening:', addr)
})
 
var http = require('http')
 
var server = http.createServer(function () {
  // ...
})
 
server.listen(0) // will trigger the above listener

API

var emitter = onnetlisten(onlistening)

Start listening for when TCP servers start listening.

The returned event emitter emits listening when that happens with the address object for the tcp server that started listening.

To stop the listener do emitter.destroy()

Acknowledgements

Credit to @andreasmadsen for writing most of this module and being an async_hooks wizard

This project was kindly sponsored by nearForm.

License

MIT