ip-address 10.3.1: Address6

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 Address6 in pkg:npm/ip-address@10.3.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/ip-address@10.3.1
Demonstrate these symbols/APIs:
  - Address6

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:c8f7e70bff422fbf4c92da2d3df06a9e36ee39c34ab706c476efe93f928390bf","contract":["Address6.isValid validates valid IPv6 addresses and rejects invalid strings","Address6 constructor parses IPv6 address and CIDR subnet mask correctly","Address6 formats canonical and correct compressed representations","Address6 calculates startAddress, endAddress, and subnet membership for IPv6 subnets","Address6 bigInt and fromBigInt convert IPv6 addresses to and from BigInt representations","Address6 identifies special address types including loopback, link-local, multicast, and ULA","Address6.fromAddress4 creates IPv4-mapped IPv6 address and converts back via to4","Address6 throws AddressError when instantiated with an invalid IP address string"],"goal":"verify Address6 in pkg:npm/ip-address@10.3.1","kind":"HOW","packages":["pkg:npm/ip-address@10.3.1"],"schemaVersion":1,"symbols":["Address6"]},"contractCommand":["node","test/contract.cjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/ip-address@10.3.1"],"schemaVersion":1,"subject":"pkg:npm/ip-address@10.3.1","symbols":["Address6"],"verifierAdapter":"node-typescript@1"}

{
  "name": "ip-address-sample",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "ip-address-sample",
      "version": "1.0.0",
      "dependencies": {
        "ip-address": "10.3.1"
      }
    },
    "node_modules/ip-address": {
      "version": "10.3.1",
      "resolved": "https://registry.npmjs.org/ip-address/-/ip-address-10.3.1.tgz",
      "integrity": "sha512-1e9d3kb97NHJTIJDZW9rKqW2h6+dFa50Dy0fpPSMQp2ADje5gvKsXmdiK6dwY5t76TaTt5+P5N1Y/LoToIxP6g==",
      "license": "MIT",
      "engines": {
        "node": ">= 12"
      }
    }
  }
}

{
  "name": "ip-address-sample",
  "version": "1.0.0",
  "private": true,
  "description": "Verification sample for Address6 in ip-address 10.3.1",
  "dependencies": {
    "ip-address": "10.3.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify Address6 in pkg:npm/ip-address@10.3.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/ip-address@10.3.1"
  ],
  "symbols": [
    "Address6"
  ]
}

const assert = require("node:assert/strict");
const { Address6, AddressError } = require("ip-address");

// 1. Address6.isValid validates valid IPv6 addresses and rejects invalid strings
assert.equal(Address6.isValid("2001:db8::1"), true);
assert.equal(Address6.isValid("::1"), true);
assert.equal(Address6.isValid("fe80::1"), true);
assert.equal(Address6.isValid("2001:0db8:85a3:0000:0000:8a2e:0370:7334"), true);
assert.equal(Address6.isValid("2001:::1"), false);
assert.equal(Address6.isValid("invalid-ipv6"), false);
assert.equal(Address6.isValid(""), false);

// 2. Address6 constructor parses IPv6 address and CIDR subnet mask correctly
const ipv6 = new Address6("2001:0db8:85a3:0000:0000:8a2e:0370:7334/64");
assert.equal(ipv6.address, "2001:0db8:85a3:0000:0000:8a2e:0370:7334/64");
assert.equal(ipv6.subnet, "/64");
assert.equal(ipv6.subnetMask, 64);
assert.deepEqual(ipv6.parsedAddress, ["2001", "db8", "85a3", "0", "0", "8a2e", "370", "7334"]);

// 3. Address6 formats canonical and correct compressed representations
assert.equal(ipv6.canonicalForm(), "2001:0db8:85a3:0000:0000:8a2e:0370:7334");
assert.equal(ipv6.correctForm(), "2001:db8:85a3::8a2e:370:7334");
assert.equal(new Address6("2001:db8:85a3::8a2e:370:7334").isCorrect(), true);

// 4. Address6 calculates startAddress, endAddress, and subnet membership for IPv6 subnets
assert.equal(ipv6.startAddress().correctForm(), "2001:db8:85a3::");
assert.equal(ipv6.endAddress().correctForm(), "2001:db8:85a3:0:ffff:ffff:ffff:ffff");
const member = new Address6("2001:db8:85a3::1");
const nonMember = new Address6("2001:db8:85a4::1");
assert.equal(member.isInSubnet(ipv6), true);
assert.equal(nonMember.isInSubnet(ipv6), false);

// 5. Address6 bigInt and fromBigInt convert IPv6 addresses to and from BigInt representations
const bi = ipv6.bigInt();
assert.equal(typeof bi, "bigint");
assert.equal(Address6.fromBigInt(bi).correctForm(), "2001:db8:85a3::8a2e:370:7334");

// 6. Address6 identifies special address types including loopback, link-local, multicast, and ULA
assert.equal(new Address6("::1").isLoopback(), true);
assert.equal(new Address6("fe80::1").isLinkLocal(), true);
assert.equal(new Address6("ff02::1").isMulticast(), true);
assert.equal(new Address6("fc00::1").isULA(), true);
assert.equal(new Address6("::").isUnspecified(), true);

// 7. Address6.fromAddress4 creates IPv4-mapped IPv6 address and converts back via to4
const v4Mapped = Address6.fromAddress4("192.168.1.1");
assert.equal(v4Mapped.isMapped4(), true);
assert.equal(v4Mapped.correctForm(), "::ffff:c0a8:101");
assert.equal(v4Mapped.to4in6(), "::ffff:192.168.1.1");
const backTo4 = v4Mapped.to4();
assert.equal(backTo4.correctForm(), "192.168.1.1");

// 8. Address6 throws AddressError when instantiated with an invalid IP address string
assert.throws(
  () => new Address6("invalid-ipv6"),
  (err) => err instanceof AddressError || err.name === "AddressError" || /Invalid/i.test(err.message)
);
assert.throws(
  () => new Address6("2001:::1"),
  (err) => err instanceof AddressError || err.name === "AddressError" || /Invalid/i.test(err.message)
);

console.log("Contract verified successfully.");