Package Exports

is-in-subnet

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (is-in-subnet) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

is-in-subnet

Check if an IPv4 or IPv6 address is contained in the given CIDR subnet.

Small
Fast
Simple syntax
Full test coverage
TypeScript-friendly
Zero dependencies
🆕 Browser-friendly

See the 📖 Reference page for complete documentation.

Installation

With Node.js

npm install is-in-subnet

In a browser

This module is compatible with Browserify and other bundling tools. If you prefer to load it as a single file from a CDN:

The module is loaded as a global named isInSubnet.

Basic Usage

Node.js

const { isInSubnet } = require('is-in-subnet');

console.log(isInSubnet('10.5.0.1', '10.4.5.0/16')); // false
console.log(isInSubnet('10.5.0.1', '10.4.5.0/15')); // true

console.log(isInSubnet('2001:db8:f53a::1', '2001:db8:f53b::1:1/48')); // false
console.log(isInSubnet('2001:db8:f53a::1', '2001:db8:f531::1:1/44')); // true

Browser

console.log(isInSubnet.isInSubnet('10.5.0.1', '10.4.5.0/16'));
// if you don’t like that syntax, you may use this instead:
console.log(isInSubnet.check('10.5.0.1', '10.4.5.0/16'));

More ways to use it

Test multiple subnets at once

You can pass an array instead of a single subnet.

const inAnySubnet = isInSubnet('10.5.0.1', ['10.4.5.0/16', '192.168.1.0/24']);

Amortise the parsing cost using a functional version

createChecker(subnetOrSubnets) returns a function used to check an address

const checker = createChecker(['10.4.5.0/16', '192.168.1.0/24']);
console.log(checker('10.5.0.1')); // true

Test for special types of addresses

isPrivate(address) — Private addresses (like 192.168.0.0)
isLocalhost(address) — Localhost addresses (like ::1)

And more. See the documentation.

Check if an address is valid

isIPv4(address), isIPv6(address), isIP(address) — works just like the similarly-named functions in Node’s net module.