find-free-ports

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.

✔️ TypeScript support

✔️ No dependencies

✔️ Should work on all major NodeJS versions

✔️ Now automatically tested for mistakes

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.

🔍 Found an issue? Please let me know in the [issue tracker][1] and we'll get
it fixed ASAP.

[1]: https://github.com/samvv/node-find-free-ports/issues

``
npm i find-free-ports
`

Usage

Import the library:

`js
import findFreePorts from "find-free-ports"
`
or
`js
const findFreePorts = require('find-free-ports');
`

Next, call the main function with the amount of free ports you need:

`js
async function startMultipleServers() {
const [a, b, c, d] = await findFreePorts(4);
// now do something interesting with the new ports ...
}
`

API

$3

`js
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 to 1025.
- endPort: prevent the scanner from exceeding this port number. Defaults to
65535.
- jobCount: how much workers that may at most be looking for free ports

$3

`js
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.

$3

`js
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

- portfinder
- get-port
- find-free-port
- freeport

License

The MIT License