cidrLastAddress - cidr.ts - @hertzg/ip documentation

function cidrLastAddress



cidrLastAddress<T extends Cidr>(cidr: T): T extends Cidrv6 ? bigint : number

Returns the last address of a CIDR block.

Dispatches to cidrv4LastAddress or cidrv6LastAddress based on the address type. Together with cidrFirstAddress this gives the numeric bounds of a block without knowing its version — the pair sorting, range comparison, and interval arithmetic want.

Note the versions differ in what the last address means: for IPv4 it is the directed broadcast address and is not assignable (cidrv4BroadcastAddress), while IPv6 has no broadcast address and the last address is assignable.

Examples

Example 1

import { assertEquals } from "@std/assert";
import { cidrLastAddress, parseCidr } from "@hertzg/ip/cidr";
import { stringifyAddress } from "@hertzg/ip/address";

assertEquals(stringifyAddress(cidrLastAddress(parseCidr("192.168.1.0/24"))), "192.168.1.255");
assertEquals(stringifyAddress(cidrLastAddress(parseCidr("2001:db8::/120"))), "2001:db8::ff");

The bounds of a block, without knowing its version

import { assertEquals } from "@std/assert";
import { cidrFirstAddress, cidrLastAddress, parseCidr } from "@hertzg/ip/cidr";
import { stringifyAddress } from "@hertzg/ip/address";

const v4 = parseCidr("10.0.0.0/29");
assertEquals(stringifyAddress(cidrFirstAddress(v4)), "10.0.0.0");
assertEquals(stringifyAddress(cidrLastAddress(v4)), "10.0.0.7");

const v6 = parseCidr("fd00::/125");
assertEquals(stringifyAddress(cidrFirstAddress(v6)), "fd00::");
assertEquals(stringifyAddress(cidrLastAddress(v6)), "fd00::7");

Type Parameters



T extends Cidr

Parameters



cidr: T

The CIDR block

Return Type

T extends Cidrv6 ? bigint : number

The last address (number for IPv4, bigint for IPv6)