first-open-port

About | Installation | Usage | License

About

A tiny Node.js module to get the first available port on localhost in a given range. Handy for avoiding hard-coded port conflicts (EADDRINUSE) if you frequently spin up more than one local server during development. Returns a Promise.

Installation

Install and require as a standard Node module.

Install

  $ npm install --save first-open-port

Require

  var firstOpenPort = require('first-open-port')

Usage

firstOpenPort(start, max)

• start : Number : begin search at this port
• (max) : Number : optional last port to search before rejecting

Returns a bluebird Promise that resolves with the first open port or rejects with an error if no open ports are found in the given range.

var firstOpenPort = require('first-open-port')

firstOpenPort(3000, 3100)
  .then(port => {
    // start a server on that port
  })
  .catch(err => {
    // do something when no ports are available
  })

License

MIT