portfinder
Advanced tools
Package description
The portfinder npm package is a utility for getting a port number that is guaranteed to be free on the current machine. It is useful for running servers on dynamically assigned ports to avoid conflicts.
Get an available port
This feature allows you to find an available port on the machine. The `getPort` function takes a callback that provides the port number.
const portfinder = require('portfinder');
portfinder.getPort((err, port) => {
if (err) {
throw err;
}
console.log('Available port found:', port);
});Set the base port
Before calling `getPort`, you can set the `basePort` property to tell portfinder to start searching for a free port from a certain number.
const portfinder = require('portfinder');
portfinder.basePort = 3000;
portfinder.getPort((err, port) => {
if (err) {
throw err;
}
console.log('Available port found:', port);
});Set the range of ports to search
You can specify a range of ports for portfinder to search within by providing an options object with `port` and `stopPort` properties.
const portfinder = require('portfinder');
portfinder.getPort({
port: 3000, // minimum port
stopPort: 3333 // maximum port
}, (err, port) => {
if (err) {
throw err;
}
console.log('Available port found:', port);
});Similar to portfinder, get-port is a package that helps you get an available TCP port to listen on. Unlike portfinder, get-port returns a Promise and supports async/await syntax, which can be more convenient in modern Node.js applications.
Detect-port is another package that checks for an available port on your machine. It is similar to portfinder but also allows you to check if a specific port is available and returns an alternative if it's not, which can be useful for suggesting the next available port.
Readme
$ npm install portfinder
The portfinder module has a simple interface:
var portfinder = require('portfinder');
portfinder.getPort(function (err, port) {
//
// `port` is guaranteed to be a free port
// in this scope.
//
});
Or with promise (if Promises are supported) :
const portfinder = require('portfinder');
portfinder.getPortPromise()
.then((port) => {
//
// `port` is guaranteed to be a free port
// in this scope.
//
})
.catch((err) => {
//
// Could not get a free port, `err` contains the reason.
//
});
If portfinder.getPortPromise() is called on a Node version without Promise (<4), it will throw an Error unless Bluebird or any Promise pollyfill is used.
By default portfinder will start searching from 8000 and scan until maximum port number (65535) is reached.
You can change this globally by setting:
portfinder.setBasePort(3000); // default: 8000
portfinder.setHighestPort(3333); // default: 65535
or by passing optional options object on each invocation:
portfinder.getPort({
port: 3000, // minimum port
stopPort: 3333 // maximum port
}, callback);
$ npm test
FAQs
A simple tool to find an open port on the current machine
The npm package portfinder receives a total of 5,992,002 weekly downloads. As such, portfinder popularity was classified as popular.
We found that portfinder demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 2 open source maintainers collaborating on the project.
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