ipv46

ipv46 is a small JavaScript library for parsing, formatting and sorting IPv4/6 addresses. It works on both Node.js and browser environments.

Note

While this package is still evolving, we're currently not accepting any new feature requests or suggestions. Please use the issue tracker for bug reports and security concerns, which we highly value and welcome. Thank you for your understanding ❤️

Installation

$ npm install @badrap/ipv46

Usage

import { IP } from "@badrap/ipv46";

IP.parse(string)

Returns the given string parsed into an IPv4 or IPv6 address object. If the string is not a valid address then the result is null.

IP.parse("192.0.2.1"); // IPv4 { ... }
IP.parse("2001:db8::1"); // IPv6 { ... }
IP.parse("non-address"); // null

IP.parse supports IPv6 addresses with embedded IPv4 addresses.

IP.parse("2001:db8::192.0.2.1"); // IPv6 { ... }

IP#version

Valid IPv4/6 address objects have their version as an attribute.

IP.parse("192.0.2.1").version; // 4
IP.parse("2001:db8::1").version; // 6

IP#toString()

Address objects implement the toString method for turning the addresses back into strings. The strings are printed lower-cased sans any extra leading zeroes. IPv6 formatting follows the RFC 5952 recommendations, except that formatting doesn't output IPv6 addresses with embedded IPv4 addresses.

IP.parse("192.0.2.1").toString(); // '192.0.2.1'
IP.parse("2001:db8::1").toString(); // '2001:db8::1'
IP.parse("2001:db8::192.0.2.1").toString(); // '2001:db8::c000:201'

IP.cmp(other)

Compare and sort addresses. IP.cmp(a, b) returns:

• -1 if a is sorted before b
• 0 if a equals b
• 1 otherwise

const a = IP.parse("192.0.2.1");
const b = IP.parse("203.0.113.0");

IP.cmp(a, a); // 0
IP.cmp(a, b); // -1
IP.cmp(b, a); // 1

IPv4 addresses are always sorted before IPv6 addresses.

const ipv4 = IP.parse("192.0.2.1");
const ipv6 = IP.parse("2001:db8::1");

IP.cmp(ipv4, ipv6); // -1

Parsed addresses get normalized. For example extra leading zeroes don't matter in comparisons.

const a = IP.parse("2001:0db8::1");
const b = IP.parse("2001:0db8:0000::0001");

IP.cmp(a, b); // 0

IP.cmp is directly compatible with Array#sort.

const a = IP.parse("2001:0db8::2");
const b = IP.parse("2001:0db8::1");
const c = IP.parse("2001:0db8::")

  [(a, b, c)].sort(IP.cmp); // [c, b, a]