pvutils 1.2.0: arrayBufferToString

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 pvutils.arrayBufferToString in pkg:npm/pvutils@1.2.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/pvutils@1.2.0
Demonstrate these symbols/APIs:
  - pvutils.arrayBufferToString
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:cd2fb90c9630d87b7a310a63a2deb51c42f56ae288c38bc9deb6e037067f4311","constraints":{"executionContext":"node"},"contract":["arrayBufferToString converts an ArrayBuffer of character codes into a string","arrayBufferToString returns an empty string when given an empty ArrayBuffer","arrayBufferToString correctly decodes multi-byte binary sequences","arrayBufferToString reconstructs text converted to ArrayBuffer via stringToArrayBuffer","arrayBufferToString works with sliced ArrayBuffers and sub-ranges"],"goal":"verify pvutils.arrayBufferToString in pkg:npm/pvutils@1.2.0","kind":"HOW","packages":["pkg:npm/pvutils@1.2.0"],"schemaVersion":1,"symbols":["pvutils.arrayBufferToString"]},"contractCommand":["node","test/contract.js"],"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/pvutils@1.2.0"],"schemaVersion":1,"subject":"pkg:npm/pvutils@1.2.0","symbols":["pvutils.arrayBufferToString"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-pvutils",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-pvutils",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "pvutils": "1.2.0"
      }
    },
    "node_modules/pvutils": {
      "version": "1.2.0",
      "resolved": "https://registry.npmjs.org/pvutils/-/pvutils-1.2.0.tgz",
      "integrity": "sha512-BbubeCEyTuQjVMakvJQ/Sxbc93F2pwmbsxONT/ZRrwU7Ua38d8unYTwXpTVLAKJ4BDuH9IGztCjQcd/N/39Dvg==",
      "license": "MIT",
      "engines": {
        "node": ">=16.0.0"
      }
    }
  }
}

{
  "name": "sample-pvutils",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for pvutils",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "pvutils": "1.2.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pvutils.arrayBufferToString in pkg:npm/pvutils@1.2.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/pvutils@1.2.0"
  ],
  "symbols": [
    "pvutils.arrayBufferToString"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const pvutils = require('pvutils');

/**
 * Converts an ArrayBuffer to a string by decoding each byte to its character code.
 * @param {ArrayBuffer} buffer - Input ArrayBuffer.
 * @returns {string} Decoded string.
 */
function bufferToString(buffer) {
  return pvutils.arrayBufferToString(buffer);
}

/**
 * Converts a string to an ArrayBuffer.
 * @param {string} str - Input string.
 * @returns {ArrayBuffer} Converted ArrayBuffer.
 */
function stringToBuffer(str) {
  return pvutils.stringToArrayBuffer(str);
}

module.exports = {
  pvutils,
  bufferToString,
  stringToBuffer
};

const assert = require('node:assert');
const pvutils = require('pvutils');
const { bufferToString, stringToBuffer } = require('../src/index.js');

// 1. arrayBufferToString converts an ArrayBuffer of character codes into a string
const helloBytes = new Uint8Array([72, 101, 108, 108, 111]); // 'Hello'
const helloBuf = helloBytes.buffer;
assert.strictEqual(pvutils.arrayBufferToString(helloBuf), 'Hello');
assert.strictEqual(bufferToString(helloBuf), 'Hello');

// 2. arrayBufferToString returns an empty string when given an empty ArrayBuffer
const emptyBuf = new ArrayBuffer(0);
assert.strictEqual(pvutils.arrayBufferToString(emptyBuf), '');
assert.strictEqual(bufferToString(emptyBuf), '');

// 3. arrayBufferToString correctly decodes multi-byte binary sequences
const binaryBytes = [0x00, 0x01, 0x7F, 0x80, 0xAA, 0xFF];
const binBuf = new Uint8Array(binaryBytes).buffer;
const expectedBinaryStr = binaryBytes.map(b => String.fromCharCode(b)).join('');
assert.strictEqual(pvutils.arrayBufferToString(binBuf), expectedBinaryStr);
assert.strictEqual(bufferToString(binBuf), expectedBinaryStr);

// 4. arrayBufferToString reconstructs text converted to ArrayBuffer via stringToArrayBuffer
const sample = 'CodeSampleX pvutils arrayBufferToString contract test string';
const encoded = stringToBuffer(sample);
assert.strictEqual(pvutils.arrayBufferToString(encoded), sample);
assert.strictEqual(bufferToString(encoded), sample);

// 5. arrayBufferToString works with sliced ArrayBuffers and sub-ranges
const rangeBuf = new Uint8Array([65, 66, 67, 68, 69]).buffer; // 'ABCDE'
const sliced = rangeBuf.slice(1, 4); // 'BCD'
assert.strictEqual(pvutils.arrayBufferToString(sliced), 'BCD');
assert.strictEqual(bufferToString(sliced), 'BCD');

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