detect-port-alt

What is detect-port-alt?

The detect-port-alt npm package is a utility that helps in checking if a port is already in use and if so, it can suggest an alternative port that is free. This is particularly useful in network programming and development environments where handling port conflicts efficiently is crucial.

What are detect-port-alt's main functionalities?

Check if a port is in use

This feature allows you to check if a specific port (e.g., 3000) is available. If the port is occupied, it suggests another free port.

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

detectPort(3000, (err, port) => {
  if (err) {
    console.error(err);
  } else if (port === 3000) {
    console.log('Port 3000 is available');
  } else {
    console.log('Port 3000 is occupied. Try port:', port);
  }
});

Promise-based port detection

This feature provides a promise-based API to check for port availability, making it easier to integrate with modern JavaScript applications using async/await.

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

async function getAvailablePort(startingPort) {
  try {
    const port = await detectPort(startingPort);
    console.log(`Port ${port} is available`);
    return port;
  } catch (error) {
    console.error('Error:', error);
  }
}

getAvailablePort(3000);

Other packages similar to detect-port-alt

portfinder

Portfinder is a popular npm package that also helps in finding an open port on the current machine. Unlike detect-port-alt, portfinder provides more configuration options such as setting a range of ports to check. This can be particularly useful when you need to find multiple free ports within a specific range.

get-port

Get-port is another similar package that provides an easy-to-use API to get an available port. It's very minimalistic compared to detect-port-alt and does not provide callback support, focusing solely on promises, which makes it suitable for use in applications fully based on modern JavaScript features.

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