cidr-to-regexp

cidr-to-regexp is an npm module that converts CIDR (Classless Inter-Domain Routing) notation to regular expression. This can be useful for validating or matching IP addresses within a specified range. Created based on this gist (kudos for @ollyg & @radu-c).

Installation

You can install the module using npm:

1npm i cidr-to-regexp

Usage

Here are some examples of how to use the cidr-to-regexp module:

Example 1: Convert CIDR to RegExp

1import cidrToRegexp from 'cidr-to-regexp';
2
3const cidr = '192.168.0.0/24';
4const regexp = cidrToRegexp(cidr);
5
6console.log(regexp); // Output: /^192\.168\.0\.(?:1[0-9]{2}|2[0-4][0-9]|25[0-5]|[1-9]?[0-9])$/

Example 2: Validate an IP Address

1import cidrToRegexp from 'cidr-to-regexp';
2
3const cidr = '192.168.0.0/24';
4const regexp = cidrToRegexp(cidr);
5const ip = '192.168.0.1';
6
7console.log(regexp.test(ip)); // Output: true

Example 3: Match IP Addresses in a Range

1import cidrToRegexp from 'cidr-to-regexp';
2
3const cidr = '10.0.0.0/8';
4const regexp = cidrToRegexp(cidr);
5const ips = ['10.0.0.1', '10.1.2.3', '192.168.1.1'];
6
7const matchedIps = ips.filter(ip => regexp.test(ip));
8
9console.log(matchedIps); // Output: ['10.0.0.1', '10.1.2.3']

API

cidrToRegexp(cidr)

• cidr (string): The CIDR notation to convert.
• Returns: A RegExp object that matches IP addresses within the specified CIDR range.