find-free-port
Find free tcp port or ports to listen locally.
Installation
npm install find-free-port --save
Examples
Find a free port to listen on that is >= 3000
var fp = require("find-free-port")
fp(3000, function(err, freePort){
});
Find a free port to listen on that is >= 3000 and < 3100
var fp = require("find-free-port")
fp(3000, 3100, function(err, freePort){
});
Find a free port to listen on that is >= 3000 and < 3100 and bound to ip 127.0.0.1
var fp = require("find-free-port")
fp(3000, 3100, '127.0.0.1', function(err, freePort){
});
Find a free port to listen on that is >= 3000 and bound to ip 127.0.0.1
var fp = require('find-free-port')
fp(3000, '127.0.0.1', function(err, freePort){
});
Find 3 free ports to listen on that is >= 3000 and bound to ip 127.0.0.1
var fp = require("find-free-port")
fp(3000, 3100, '127.0.0.1', 3, function(err, p1, p2, p3){
});
Promise
If the callback is omitted, then the call returns a Promise that resolve to a list of avaiable ports:
var fp = require("find-free-port")
fp(3000).then(([freep]) => {
console.log('found ' + freep);
}).catch((err)=>{
console.error(err);
});