crc32-stream 4.0.3: CRC32Stream

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 crc32-stream.CRC32Stream in pkg:npm/crc32-stream@4.0.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/crc32-stream@4.0.3
Demonstrate these symbols/APIs:
  - crc32-stream.CRC32Stream

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:sha256:32e780438fc35c88c77664bd66e63a72afb24584b9b86a9c7ddaae1d4154bb82","contract":["CRC32Stream instantiates as a Transform stream with initial size 0 and initial hex checksum 00000000","CRC32Stream transforms data chunks transparently while tracking processed byte length via size()","CRC32Stream computes standard CRC32 checksums accessible as Buffer via digest() or uppercase string via hex()"],"goal":"verify crc32-stream.CRC32Stream in pkg:npm/crc32-stream@4.0.3","kind":"HOW","packages":["pkg:npm/crc32-stream@4.0.3"],"schemaVersion":1,"symbols":["crc32-stream.CRC32Stream"]},"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/crc32-stream@4.0.3"],"schemaVersion":1,"subject":"pkg:npm/crc32-stream@4.0.3","symbols":["crc32-stream.CRC32Stream"],"verifierAdapter":"node-typescript@1"}

'use strict';

const { CRC32Stream } = require('crc32-stream');

function createCRC32Stream(options) {
  return new CRC32Stream(options);
}

function calculateCRC32(buffer) {
  return new Promise((resolve, reject) => {
    const stream = new CRC32Stream();
    stream.on('finish', () => {
      resolve({
        size: stream.size(),
        hex: stream.hex(),
        digest: stream.digest()
      });
    });
    stream.on('error', reject);
    stream.end(buffer);
  });
}

module.exports = {
  CRC32Stream,
  createCRC32Stream,
  calculateCRC32
};

{
  "name": "sample-crc32-stream",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-crc32-stream",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "crc32-stream": "4.0.3"
      }
    },
    "node_modules/crc-32": {
      "version": "1.2.2",
      "resolved": "https://registry.npmjs.org/crc-32/-/crc-32-1.2.2.tgz",
      "integrity": "sha512-ROmzCKrTnOwybPcJApAA6WBWij23HVfGVNKqqrZpuyZOHqK2CwHSvpGuyt/UNNvaIjEd8X5IFGp4Mh+Ie1IHJQ==",
      "license": "Apache-2.0",
      "bin": {
        "crc32": "bin/crc32.njs"
      },
      "engines": {
        "node": ">=0.8"
      }
    },
    "node_modules/crc32-stream": {
      "version": "4.0.3",
      "resolved": "https://registry.npmjs.org/crc32-stream/-/crc32-stream-4.0.3.tgz",
      "integrity": "sha512-NT7w2JVU7DFroFdYkeq8cywxrgjPHWkdX1wjpRQXPX5Asews3tA+Ght6lddQO5Mkumffp3X7GEqku3epj2toIw==",
      "license": "MIT",
      "dependencies": {
        "crc-32": "^1.2.0",
        "readable-stream": "^3.4.0"
      },
      "engines": {
        "node": ">= 10"
      }
    },
    "node_modules/inherits": {
      "version": "2.0.4",
      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
      "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ==",
      "license": "ISC"
    },
    "node_modules/readable-stream": {
      "version": "3.6.2",
      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
      "license": "MIT",
      "dependencies": {
        "inherits": "^2.0.3",
        "string_decoder": "^1.1.1",
        "util-deprecate": "^1.0.1"
      },
      "engines": {
        "node": ">= 6"
      }
    },
    "node_modules/safe-buffer": {
      "version": "5.2.1",
      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
      "integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/feross"
        },
        {
          "type": "patreon",
          "url": "https://www.patreon.com/feross"
        },
        {
          "type": "consulting",
          "url": "https://feross.org/support"
        }
      ],
      "license": "MIT"
    },
    "node_modules/string_decoder": {
      "version": "1.3.0",
      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.3.0.tgz",
      "integrity": "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA==",
      "license": "MIT",
      "dependencies": {
        "safe-buffer": "~5.2.0"
      }
    },
    "node_modules/util-deprecate": {
      "version": "1.0.2",
      "resolved": "https://registry.npmjs.org/util-deprecate/-/util-deprecate-1.0.2.tgz",
      "integrity": "sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-crc32-stream",
  "version": "1.0.0",
  "private": true,
  "description": "verify crc32-stream.CRC32Stream in pkg:npm/crc32-stream@4.0.3",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.cjs"
  },
  "dependencies": {
    "crc32-stream": "4.0.3"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify crc32-stream.CRC32Stream in pkg:npm/crc32-stream@4.0.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/crc32-stream@4.0.3"
  ],
  "symbols": [
    "crc32-stream.CRC32Stream"
  ]
}

'use strict';

const assert = require('assert');
const { Readable } = require('stream');
const { CRC32Stream, createCRC32Stream, calculateCRC32 } = require('../index.js');

async function run() {
  // 1. Instantiation and initial state
  const initial = new CRC32Stream();
  assert.strictEqual(initial.size(), 0, 'Initial size must be 0');
  assert.strictEqual(initial.hex(), '00000000', 'Initial hex must be 00000000');
  assert.strictEqual(initial.digest('hex'), '00000000', 'Initial digest hex must be 00000000');
  assert.deepStrictEqual(initial.digest(), Buffer.from([0, 0, 0, 0]), 'Initial digest buffer must be 4 zero bytes');

  // 2. Transparent streaming transformation and size tracking
  const inputChunks = [Buffer.from('hello '), Buffer.from('world')];
  const expectedContent = 'hello world';
  const stream = new CRC32Stream();
  const collectedChunks = [];

  const streamPromise = new Promise((resolve, reject) => {
    stream.on('data', (chunk) => {
      collectedChunks.push(chunk);
    });
    stream.on('finish', () => {
      resolve();
    });
    stream.on('error', reject);
  });

  const readable = Readable.from(inputChunks);
  readable.pipe(stream);
  await streamPromise;

  const transformed = Buffer.concat(collectedChunks).toString('utf8');
  assert.strictEqual(transformed, expectedContent, 'CRC32Stream must pass through data chunks transparently');
  assert.strictEqual(stream.size(), Buffer.byteLength(expectedContent), 'size() must match total processed bytes');

  // 3. Known test vector: "123456789" -> 0xCBF43926
  const vectorResult = await calculateCRC32(Buffer.from('123456789'));
  assert.strictEqual(vectorResult.size, 9, 'Vector size must be 9 bytes');
  assert.strictEqual(vectorResult.hex, 'CBF43926', 'hex() must return uppercase standard CRC32 hex string');
  assert.strictEqual(vectorResult.digest.toString('hex'), 'cbf43926', 'digest() buffer must contain matching CRC32 bytes');

  // 4. Helper factory
  const factoryStream = createCRC32Stream();
  assert(factoryStream instanceof CRC32Stream, 'createCRC32Stream must return a CRC32Stream instance');

  console.log('Contract tests passed successfully.');
}

run().catch((err) => {
  console.error('Contract test failed:', err);
  process.exit(1);
});