This is a very small package that allows developers to find free ports on the local system. Unlike most other "find-free-port" utilities, this library allows scanning for multiple free ports at once, making sure that there are no doubles in the result.
This library has been benchmarked and parallelises the port checks using a customisable number of workers for optimal performance. The alogithm does not create a new anonymous socket for each port, but instead iterates in parallell over the system's port numbers. This is both faster and less resource-intensive.
npm i find-free-ports
Usage
Import the library:
import findFreePorts from "find-free-ports"or
const findFreePorts = require('find-free-ports');Next, call the main function with the amount of free ports you need:
async function startMultipleServers() {
const [a, b, c, d] = await findFreePorts(4);
// now do something interesting with the new ports ...
}API
findFreePorts(count?, opts?)
import { findFreePorts } from "find-free-ports"Search for the specified amount of free ports on the local machine. If count
is left unspecified, it defaults to 1. opts may be a dictionary containing one
of the following keys:
-
isFree: custom function that is used to check whether the given port is free -
startPort: start scanning for free ports starting from this port number. Defaults to1025. -
endPort: prevent the scanner from exceeding this port number. Defaults to65535. -
jobCount: how much workers that may at most be looking for free ports
isFreePort(port)
import { isFreePort } from "find-free-ports"Check whether the given port is free by trying to set up a socket.
This function returns a promise containing either true or false depending
on whether the port was available.
FindFreePortsOptions
import { FindFreePortsOptions } from "find-free-ports"A TypeScript interface that lists all valid options that may be passed as the
opts parameter to findFreePorts().
Similar Packages
License
The MIT License