buffer 5.7.1: Buffer

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 buffer.Buffer in pkg:npm/buffer@5.7.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/buffer@5.7.1
Demonstrate these symbols/APIs:
  - buffer.Buffer

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:ee4cad80291545610dfbe88805a90a430b85f85d00c2ab73a28e5286cf81b6ca","contract":["buffer.Buffer.from creates Buffer instances from utf8 string, hex string, and byte array","buffer.Buffer.alloc allocates fixed-size zero-filled and filled buffers","buffer.Buffer.isBuffer accurately checks for Buffer instances","buffer.Buffer.concat combines multiple buffers into a single buffer","buffer.Buffer.byteLength measures correct byte length across utf8, hex, and base64 encodings","buffer.Buffer instance supports slice, copy, write, and toString encoding conversions","buffer.Buffer.compare compares buffer instances lexicographically","buffer.Buffer throws TypeError or RangeError on invalid constructor and allocation arguments"],"goal":"verify buffer.Buffer in pkg:npm/buffer@5.7.1","kind":"HOW","packages":["pkg:npm/buffer@5.7.1"],"schemaVersion":1,"symbols":["buffer.Buffer"]},"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/buffer@5.7.1"],"schemaVersion":1,"subject":"pkg:npm/buffer@5.7.1","symbols":["buffer.Buffer"],"verifierAdapter":"node-typescript@1"}

import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const bufferPkg = require('buffer/');
export const Buffer = bufferPkg.Buffer;
export default bufferPkg;

{
  "name": "sample-buffer-buffer",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-buffer-buffer",
      "version": "1.0.0",
      "dependencies": {
        "buffer": "5.7.1"
      }
    },
    "node_modules/base64-js": {
      "version": "1.5.1",
      "resolved": "https://registry.npmjs.org/base64-js/-/base64-js-1.5.1.tgz",
      "integrity": "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA==",
      "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/buffer": {
      "version": "5.7.1",
      "resolved": "https://registry.npmjs.org/buffer/-/buffer-5.7.1.tgz",
      "integrity": "sha512-EHcyIPBQ4BSGlvjB16k5KgAJ27CIsHY/2JBmCRReo48y9rQ3MaUzWX3KVlBa4U7MyX02HdVj0K7C3WaB3ju7FQ==",
      "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",
      "dependencies": {
        "base64-js": "^1.3.1",
        "ieee754": "^1.1.13"
      }
    },
    "node_modules/ieee754": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/ieee754/-/ieee754-1.2.1.tgz",
      "integrity": "sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA==",
      "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": "BSD-3-Clause"
    }
  }
}

{
  "name": "sample-buffer-buffer",
  "version": "1.0.0",
  "type": "module",
  "main": "index.mjs",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "buffer": "5.7.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify buffer.Buffer in pkg:npm/buffer@5.7.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/buffer@5.7.1"
  ],
  "symbols": [
    "buffer.Buffer"
  ]
}

import assert from 'node:assert/strict';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);
const buffer = require('buffer/');
const { Buffer } = buffer;

// 1. buffer.Buffer.from creates Buffer instances from utf8 string, hex string, and byte array
{
  const utf8Buf = Buffer.from('hello world', 'utf8');
  assert.ok(Buffer.isBuffer(utf8Buf));
  assert.equal(utf8Buf.toString('utf8'), 'hello world');
  assert.equal(utf8Buf.length, 11);

  const hexBuf = Buffer.from('68656c6c6f', 'hex');
  assert.ok(Buffer.isBuffer(hexBuf));
  assert.equal(hexBuf.toString('utf8'), 'hello');

  const byteArrBuf = Buffer.from([104, 101, 108, 108, 111]);
  assert.ok(Buffer.isBuffer(byteArrBuf));
  assert.equal(byteArrBuf.toString('utf8'), 'hello');
}

// 2. buffer.Buffer.alloc allocates fixed-size zero-filled and filled buffers
{
  const zeroBuf = Buffer.alloc(8);
  assert.ok(Buffer.isBuffer(zeroBuf));
  assert.equal(zeroBuf.length, 8);
  assert.deepEqual(Array.from(zeroBuf), [0, 0, 0, 0, 0, 0, 0, 0]);

  const filledBuf = Buffer.alloc(4, 0x41);
  assert.equal(filledBuf.toString('utf8'), 'AAAA');
}

// 3. buffer.Buffer.isBuffer accurately checks for Buffer instances
{
  assert.equal(Buffer.isBuffer(Buffer.alloc(4)), true);
  assert.equal(Buffer.isBuffer(Buffer.from('test')), true);
  assert.equal(Buffer.isBuffer(new Uint8Array(4)), false);
  assert.equal(Buffer.isBuffer('not a buffer'), false);
  assert.equal(Buffer.isBuffer(null), false);
  assert.equal(Buffer.isBuffer(undefined), false);
  assert.equal(Buffer.isBuffer({}), false);
}

// 4. buffer.Buffer.concat combines multiple buffers into a single buffer
{
  const part1 = Buffer.from('Hello, ');
  const part2 = Buffer.from('world!');
  const combined = Buffer.concat([part1, part2]);
  assert.ok(Buffer.isBuffer(combined));
  assert.equal(combined.toString('utf8'), 'Hello, world!');
  assert.equal(combined.length, 13);
}

// 5. buffer.Buffer.byteLength measures correct byte length across utf8, hex, and base64 encodings
{
  assert.equal(Buffer.byteLength('hello', 'utf8'), 5);
  assert.equal(Buffer.byteLength('가나다', 'utf8'), 9);
  assert.equal(Buffer.byteLength('68656c6c6f', 'hex'), 5);
  assert.equal(Buffer.byteLength('aGVsbG8=', 'base64'), 5);
}

// 6. buffer.Buffer instance supports slice, copy, write, and toString encoding conversions
{
  const buf = Buffer.alloc(10);
  const written = buf.write('hello', 0, 5, 'utf8');
  assert.equal(written, 5);
  assert.equal(buf.slice(0, 5).toString('utf8'), 'hello');

  const target = Buffer.alloc(5);
  buf.copy(target, 0, 0, 5);
  assert.equal(target.toString('utf8'), 'hello');
  assert.equal(target.toString('hex'), '68656c6c6f');
  assert.equal(target.toString('base64'), 'aGVsbG8=');
}

// 7. buffer.Buffer.compare compares buffer instances lexicographically
{
  const bufA = Buffer.from('apple');
  const bufB = Buffer.from('banana');
  assert.equal(Buffer.compare(bufA, bufB), -1);
  assert.equal(Buffer.compare(bufB, bufA), 1);
  assert.equal(Buffer.compare(bufA, bufA), 0);
  assert.equal(bufA.compare(bufB), -1);
}

// 8. buffer.Buffer throws TypeError or RangeError on invalid constructor and allocation arguments
{
  assert.throws(
    () => Buffer.from(123),
    {
      name: 'TypeError'
    }
  );
  assert.throws(
    () => Buffer.alloc(-1),
    {
      name: 'RangeError'
    }
  );
  assert.throws(
    () => Buffer.alloc('invalid'),
    {
      name: 'TypeError'
    }
  );
  assert.throws(
    () => Buffer.concat('not-an-array'),
    {
      name: 'TypeError'
    }
  );
}

console.log('All buffer.Buffer contract assertions passed.');