detect-port

What is detect-port?

The detect-port npm package is a utility for detecting available network ports on a machine. It is useful for scenarios where you need to find an open port to start a server or service.

What are detect-port's main functionalities?

Detecting an available port

This feature allows you to check if a specific port is available. If the port is occupied, it suggests an alternative available port.

const detect = require('detect-port');

const port = 3000;
detect(port, (err, _port) => {
  if (err) {
    console.log(err);
  }
  if (port === _port) {
    console.log(`port ${port} was not occupied`);
  } else {
    console.log(`port ${port} was occupied, try port ${_port}`);
  }
});

Promise-based port detection

This feature provides a promise-based approach to detect an available port, making it easier to integrate with modern JavaScript code that uses async/await.

const detect = require('detect-port');

const port = 3000;
detect(port).then(_port => {
  if (port === _port) {
    console.log(`port ${port} was not occupied`);
  } else {
    console.log(`port ${port} was occupied, try port ${_port}`);
  }
}).catch(err => {
  console.log(err);
});

Other packages similar to detect-port

portfinder

The portfinder package is another utility for finding open ports. It offers similar functionality to detect-port but includes additional features like specifying a range of ports to search within. It is also promise-based and has a more extensive API.

get-port

The get-port package is a lightweight utility for finding an available port. It is similar to detect-port but focuses on simplicity and ease of use. It is promise-based and allows specifying a preferred port or a range of ports.

README

---

JavaScript Implementation of Port Detector

Usage

$ npm i detect-port --save

const detect = require('detect-port');

/**
 * callback usage
 */

detect(port, (err, _port) => {
  if (err) {
    console.log(err);
  }

  if (port === _port) {
    console.log(`port: ${port} was not occupied`);
  } else {
    console.log(`port: ${port} was occupied, try port: ${_port}`);
  }
});

/**
 * for a yield syntax instead of callback function implement
 */

const co = require('co');

co(function *() {
  const _port = yield detect(port);

  if (port === _port) {
    console.log(`port: ${port} was not occupied`);
  } else {
    console.log(`port: ${port} was occupied, try port: ${_port}`);
  }
});

/**
 * use as a promise
 */

detect(port)
  .then(_port => {
    if (port === _port) {
      console.log(`port: ${port} was not occupied`);
    } else {
      console.log(`port: ${port} was occupied, try port: ${_port}`);
    }
  })
  .catch(err => {
    console.log(err);
  });

Command Line Tool

$ npm i detect-port -g

Quick Start

# get an available port randomly
$ detect

# detect pointed port
$ detect 80

# more help
$ detect --help

Authors

• xudafeng
• zenzhu

License

MIT

Changelog

1.0.7 / 2016-12-11

• Early return for rejected promise
  • Prevent promsie swallow in callback