You can install portfinder using a package manager like npm, yarn, or bun:
npm install portfinderThe portfinder module has a simple interface:
const portfinder = require('portfinder');
portfinder.getPort(function (err, port) {
//
// `port` is guaranteed to be a free port
// in this scope.
//
});Or using promises:
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.
//
});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: 65535or by passing optional options object on each invocation:
portfinder.getPort({
port: 3000, // minimum port
stopPort: 3333 // maximum port
}, callback);npm test