ip-address 10.7.0: Address6.endAddress, Address6.isInSubnet, Address6.startAddress

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/ip-address@10.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/ip-address@10.7.0
Demonstrate these symbols/APIs:
  - Address6.endAddress
  - Address6.isInSubnet
  - Address6.startAddress

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:b500847079c2c3ad227b414a714d157719371dd01e78948589b3afa619ce4f52","contract":["Address6.startAddress calculates the first IPv6 network address of a CIDR block and returns an Address6 instance","Address6.endAddress calculates the final broadcast IPv6 address of a CIDR block and returns an Address6 instance","Address6.isInSubnet verifies membership of host addresses and nested subnets within a target IPv6 prefix","Address6 calculates exclusive host boundaries using startAddressExclusive and endAddressExclusive"],"goal":"verify pkg:npm/ip-address@10.7.0","kind":"HOW","packages":["pkg:npm/ip-address@10.7.0"],"schemaVersion":1,"symbols":["Address6.endAddress","Address6.isInSubnet","Address6.startAddress"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/ip-address@10.7.0"],"schemaVersion":1,"subject":"pkg:npm/ip-address@10.7.0","symbols":["Address6.endAddress","Address6.isInSubnet","Address6.startAddress"],"verifierAdapter":"node-typescript@1"}

import { Address6 } from 'ip-address';

/**
 * Calculates the network boundary (start and end addresses) of an IPv6 CIDR block.
 * @param {string} cidrString
 * @returns {{ startAddress: string, endAddress: string }}
 */
export function getSubnetRange(cidrString) {
  const addr = new Address6(cidrString);
  return {
    startAddress: addr.startAddress().correctForm(),
    endAddress: addr.endAddress().correctForm()
  };
}

/**
 * Calculates the exclusive usable host boundaries of an IPv6 CIDR block.
 * @param {string} cidrString
 * @returns {{ exclusiveStart: string, exclusiveEnd: string }}
 */
export function getExclusiveSubnetRange(cidrString) {
  const addr = new Address6(cidrString);
  return {
    exclusiveStart: addr.startAddressExclusive().correctForm(),
    exclusiveEnd: addr.endAddressExclusive().correctForm()
  };
}

/**
 * Checks whether an IPv6 candidate (host or subnet) is contained within a target subnet.
 * @param {string} candidateString
 * @param {string} targetSubnetString
 * @returns {boolean}
 */
export function isAddressInSubnet(candidateString, targetSubnetString) {
  const candidate = new Address6(candidateString);
  const targetSubnet = new Address6(targetSubnetString);
  return candidate.isInSubnet(targetSubnet);
}

{
  "name": "ip-address-sample",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "ip-address-sample",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "ip-address": "10.7.0"
      }
    },
    "node_modules/ip-address": {
      "version": "10.7.0",
      "resolved": "https://registry.npmjs.org/ip-address/-/ip-address-10.7.0.tgz",
      "integrity": "sha512-BGFsyJd5mpXp3rK6jIdADLNgpJUK1jnjzvYF8lK+VyDab9JAmqN0YOKDdP17HlgKb2+ehPgDc8EtnRLbGCAMhA==",
      "license": "MIT",
      "engines": {
        "node": ">= 12"
      }
    }
  }
}

{
  "name": "ip-address-sample",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT-0",
  "dependencies": {
    "ip-address": "10.7.0"
  },
  "scripts": {
    "test": "node test/contract.mjs"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/ip-address@10.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/ip-address@10.7.0"
  ],
  "symbols": [
    "Address6.endAddress",
    "Address6.isInSubnet",
    "Address6.startAddress"
  ]
}

import assert from 'node:assert/strict';
import { Address6 } from 'ip-address';
import {
  getSubnetRange,
  getExclusiveSubnetRange,
  isAddressInSubnet
} from '../index.mjs';

// Contract 1: Address6.startAddress calculates the first IPv6 network address of a CIDR block and returns an Address6 instance
{
  const subnet64 = new Address6('2001:db8:abcd:0012::1/64');
  const start = subnet64.startAddress();
  assert.equal(start instanceof Address6, true);
  assert.equal(start.correctForm(), '2001:db8:abcd:12::');
  assert.equal(start.subnet, '/128');

  // Single host (/128)
  const host128 = new Address6('2001:db8::1/128');
  assert.equal(host128.startAddress().correctForm(), '2001:db8::1');

  // Helper function verification
  const range = getSubnetRange('2001:db8:ffff::5/48');
  assert.equal(range.startAddress, '2001:db8:ffff::');
}

// Contract 2: Address6.endAddress calculates the final broadcast IPv6 address of a CIDR block and returns an Address6 instance
{
  const subnet64 = new Address6('2001:db8:abcd:0012::1/64');
  const end = subnet64.endAddress();
  assert.equal(end instanceof Address6, true);
  assert.equal(end.correctForm(), '2001:db8:abcd:12:ffff:ffff:ffff:ffff');
  assert.equal(end.subnet, '/128');

  // Single host (/128)
  const host128 = new Address6('2001:db8::1/128');
  assert.equal(host128.endAddress().correctForm(), '2001:db8::1');

  // Helper function verification
  const range = getSubnetRange('2001:db8:ffff::5/48');
  assert.equal(range.endAddress, '2001:db8:ffff:ffff:ffff:ffff:ffff:ffff');
}

// Contract 3: Address6.isInSubnet verifies membership of host addresses and nested subnets within a target IPv6 prefix
{
  const parent = new Address6('2001:db8::/32');
  const childSubnet = new Address6('2001:db8:1234::/48');
  const insideHost = new Address6('2001:db8:ffff:ffff::1/128');
  const insideHostWithoutMask = new Address6('2001:db8::42');
  const outsideHost = new Address6('2001:db9::1/128');

  // Direct Address6 API
  assert.equal(childSubnet.isInSubnet(parent), true);
  assert.equal(insideHost.isInSubnet(parent), true);
  assert.equal(insideHostWithoutMask.isInSubnet(parent), true);
  assert.equal(outsideHost.isInSubnet(parent), false);
  assert.equal(parent.isInSubnet(childSubnet), false);

  // Helper function verification
  assert.equal(isAddressInSubnet('2001:db8:abcd::1', '2001:db8::/32'), true);
  assert.equal(isAddressInSubnet('fe80::1', '2001:db8::/32'), false);
}

// Contract 4: Address6 calculates exclusive host boundaries using startAddressExclusive and endAddressExclusive
{
  const subnet64 = new Address6('2001:db8:abcd:0012::1/64');
  const exclusiveStart = subnet64.startAddressExclusive();
  const exclusiveEnd = subnet64.endAddressExclusive();

  assert.equal(exclusiveStart.correctForm(), '2001:db8:abcd:12::1');
  assert.equal(exclusiveEnd.correctForm(), '2001:db8:abcd:12:ffff:ffff:ffff:fffe');

  // Helper function verification
  const exclusive = getExclusiveSubnetRange('2001:db8:abcd:0012::1/64');
  assert.equal(exclusive.exclusiveStart, '2001:db8:abcd:12::1');
  assert.equal(exclusive.exclusiveEnd, '2001:db8:abcd:12:ffff:ffff:ffff:fffe');
}

console.log('All contract assertions verified successfully.');