get-port 
Get an available TCP port
Install
$ npm install get-port
Usage
const getPort = require('get-port');
(async () => {
console.log(await getPort());
//=> 51402
})();Pass in a preferred port:
(async () => {
console.log(await getPort({port: 3000}));
// Will use 3000 if available, otherwise fall back to a random port
})();Pass in an array of preferred ports:
(async () => {
console.log(await getPort({port: [3000, 3001, 3002]}));
// Will use any element in the preferred ports array if available, otherwise fall back to a random port
})();API
getPort([options])
Returns a Promise for a port number.
options
Type: Object
port
Type: number number[]
A preferred port or an array of preferred ports to use.
host
Type: string
The host on which port resolution should be performed. Can be either an IPv4 or IPv6 address.
Beware
There is a very tiny chance of a race condition if another service starts using the same port number as you in between the time you get the port number and you actually start using it.
Related
- get-port-cli - CLI for this module
License
MIT © Sindre Sorhus