ip-address 10.3.1: Address4

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 Address4 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:
  - Address4
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:a7125e4289ac372feb06dbe385a4a0b9a5cd3afbe4159321ceedc85a82891b73","constraints":{"executionContext":"node"},"contract":["Address4.isValid validates valid IPv4 addresses and rejects invalid strings","Address4 constructor parses IPv4 address and CIDR subnet mask correctly","Address4 calculates startAddress, endAddress, and host boundaries for a given subnet","Address4.isInSubnet determines whether an address belongs to a specified subnet","Address4.fromAddressAndMask parses dotted-decimal subnet masks into CIDR prefix length","Address4 bigInt and fromBigInt convert IPv4 addresses to and from 32-bit integers","Address4 fromHex and toHex convert between hex string and Address4","Address4 correctForm returns the normalized dotted-decimal IP address string","Address4 throws AddressError when instantiated with an invalid IP address string"],"goal":"verify Address4 in pkg:npm/ip-address@10.3.1","kind":"HOW","packages":["pkg:npm/ip-address@10.3.1"],"schemaVersion":1,"symbols":["Address4"]},"contractCommand":["node","test/contract.cjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","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":["Address4"],"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 Address4 in ip-address 10.3.1",
  "dependencies": {
    "ip-address": "10.3.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify Address4 in pkg:npm/ip-address@10.3.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/ip-address@10.3.1"
  ],
  "symbols": [
    "Address4"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const assert = require("node:assert/strict");
const { Address4, AddressError } = require("ip-address");

// 1. Address4.isValid validates valid IPv4 addresses and rejects invalid strings
assert.equal(Address4.isValid("192.168.1.100"), true);
assert.equal(Address4.isValid("10.0.0.1"), true);
assert.equal(Address4.isValid("127.0.0.1"), true);
assert.equal(Address4.isValid("999.1.1.1"), false);
assert.equal(Address4.isValid("256.0.0.1"), false);
assert.equal(Address4.isValid("invalid-ip"), false);
assert.equal(Address4.isValid(""), false);

// 2. Address4 constructor parses IPv4 address and CIDR subnet mask correctly
const ipv4 = new Address4("192.168.1.100/24");
assert.equal(ipv4.address, "192.168.1.100/24");
assert.equal(ipv4.subnet, "/24");
assert.equal(ipv4.subnetMask, 24);
assert.deepEqual(ipv4.parsedAddress, ["192", "168", "1", "100"]);

// 3. Address4 calculates startAddress, endAddress, and host boundaries for a given subnet
assert.equal(ipv4.startAddress().correctForm(), "192.168.1.0");
assert.equal(ipv4.endAddress().correctForm(), "192.168.1.255");
assert.equal(ipv4.startAddressExclusive().correctForm(), "192.168.1.1");
assert.equal(ipv4.endAddressExclusive().correctForm(), "192.168.1.254");

// 4. Address4.isInSubnet determines whether an address belongs to a specified subnet
const member4 = new Address4("192.168.1.50");
const nonMember4 = new Address4("192.168.2.1");
assert.equal(member4.isInSubnet(ipv4), true);
assert.equal(nonMember4.isInSubnet(ipv4), false);

// 5. Address4.fromAddressAndMask parses dotted-decimal subnet masks into CIDR prefix length
const v4FromMask = Address4.fromAddressAndMask("10.0.0.1", "255.255.0.0");
assert.equal(v4FromMask.subnetMask, 16);
assert.equal(v4FromMask.startAddress().correctForm(), "10.0.0.0");
assert.equal(v4FromMask.endAddress().correctForm(), "10.0.255.255");

// 6. Address4 bigInt and fromBigInt convert IPv4 addresses to and from 32-bit integers
const v4BigInt = ipv4.bigInt();
assert.equal(typeof v4BigInt, "bigint");
assert.equal(Address4.fromBigInt(v4BigInt).correctForm(), "192.168.1.100");

// 7. Address4 fromHex and toHex convert between hex string and Address4
const hex4 = ipv4.toHex();
const fromHex4 = Address4.fromHex(hex4);
assert.equal(fromHex4.correctForm(), "192.168.1.100");

// 8. Address4 correctForm returns the normalized dotted-decimal IP address string
const addrWithSubnet = new Address4("192.168.1.1/24");
assert.equal(addrWithSubnet.correctForm(), "192.168.1.1");
assert.equal(addrWithSubnet.isCorrect(), true);
const plainAddr = new Address4("10.0.0.1");
assert.equal(plainAddr.correctForm(), "10.0.0.1");

// 9. Address4 throws AddressError when instantiated with an invalid IP address string
assert.throws(
  () => new Address4("not-an-ip"),
  (err) => {
    return err instanceof AddressError || err.name === "AddressError" || /Invalid/i.test(err.message);
  }
);
assert.throws(
  () => new Address4("300.1.1.1"),
  (err) => {
    return err instanceof AddressError || err.name === "AddressError" || /Invalid/i.test(err.message);
  }
);
assert.throws(
  () => new Address4("192.168.001.001"),
  (err) => {
    return err instanceof AddressError || err.name === "AddressError" || /zeroes/i.test(err.message);
  }
);

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