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

detect-port

Node.js implementation of port detector

Who are using or has used

• ⭐⭐⭐eggjs/egg
• ⭐⭐⭐alibaba/ice
• ⭐⭐⭐alibaba/uirecorder
• ⭐⭐⭐facebook/create-react-app
• ⭐⭐⭐facebook/flipper
• ⭐⭐⭐umijs/umi
• ⭐⭐⭐gatsbyjs/gatsby
• ⭐⭐⭐electron-react-boilerplate/electron-react-boilerplate
• ⭐⭐⭐zeit/micro
• ⭐⭐⭐rails/webpacker
• ⭐⭐⭐storybookjs/storybook

For more

Usage

npm i detect-port

CommonJS

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

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

ESM and TypeScript

import { detect } from 'detect-port';

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

# output verbose log
$ detect --verbose

# more help
$ detect --help

FAQ

Most likely network error, check that your /etc/hosts and make sure the content below:

127.0.0.1       localhost
255.255.255.255 broadcasthost
::1             localhost

License

MIT

Contributors

Made with contributors-img.

Changelog

2.1.0 (2024-12-10)

Features

• refactor with async/await instead of callback (#59) (9254c18)