isbinaryfile 4.0.10

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 pkg:npm/isbinaryfile@4.0.10
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/isbinaryfile@4.0.10

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:f639cf6bf102a4c6b826285062a52f85b5a587f0cf9ae8b395a5d0ebb14730ef","contract":["isBinaryFileSync returns false for plain text buffer and true for binary buffer","isBinaryFile asynchronously returns false for plain text buffer and true for binary buffer","isBinaryFile and isBinaryFileSync correctly detect binary status for file paths"],"goal":"verify pkg:npm/isbinaryfile@4.0.10","kind":"HOW","packages":["pkg:npm/isbinaryfile@4.0.10"],"schemaVersion":1},"contractCommand":["node","test/contract.js"],"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/isbinaryfile@4.0.10"],"schemaVersion":1,"subject":"pkg:npm/isbinaryfile@4.0.10","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-isbinaryfile",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-isbinaryfile",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "isbinaryfile": "4.0.10"
      }
    },
    "node_modules/isbinaryfile": {
      "version": "4.0.10",
      "resolved": "https://registry.npmjs.org/isbinaryfile/-/isbinaryfile-4.0.10.tgz",
      "integrity": "sha512-iHrqe5shvBUcFbmZq9zOQHBoeOhZJu6RQGrDpBgenUm/Am+F3JM2MgQj+rK3Z601fzrL5gLZWtAPH2OBaSVcyw==",
      "license": "MIT",
      "engines": {
        "node": ">= 8.0.0"
      }
    }
  }
}

{
  "name": "sample-isbinaryfile",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification sample for isbinaryfile",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "isbinaryfile": "4.0.10"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/isbinaryfile@4.0.10",
  "kind": "HOW",
  "packages": [
    "pkg:npm/isbinaryfile@4.0.10"
  ]
}

const { isBinaryFile, isBinaryFileSync } = require('isbinaryfile');

async function detectBinary(file, size) {
  return await isBinaryFile(file, size);
}

function detectBinarySync(file, size) {
  return isBinaryFileSync(file, size);
}

module.exports = {
  detectBinary,
  detectBinarySync
};

const assert = require('node:assert');
const fs = require('node:fs');
const path = require('node:path');
const os = require('node:os');
const { isBinaryFile, isBinaryFileSync } = require('isbinaryfile');
const { detectBinary, detectBinarySync } = require('../src/index.js');

async function runTests() {
  // 1. Buffer detection (synchronous)
  const textBuffer = Buffer.from('Hello world! This is plain text ASCII content.\nLine two.\n');
  const binaryBuffer = Buffer.from([0x00, 0xFF, 0x00, 0x7F, 0x80, 0xFE, 0x01, 0x02, 0x03]);

  assert.strictEqual(isBinaryFileSync(textBuffer, textBuffer.length), false, 'text buffer should not be binary');
  assert.strictEqual(detectBinarySync(textBuffer, textBuffer.length), false, 'helper text buffer sync should return false');

  assert.strictEqual(isBinaryFileSync(binaryBuffer, binaryBuffer.length), true, 'binary buffer should be binary');
  assert.strictEqual(detectBinarySync(binaryBuffer, binaryBuffer.length), true, 'helper binary buffer sync should return true');

  // 2. Buffer detection (asynchronous)
  const textAsync = await isBinaryFile(textBuffer, textBuffer.length);
  assert.strictEqual(textAsync, false, 'async text buffer should return false');
  const textHelperAsync = await detectBinary(textBuffer, textBuffer.length);
  assert.strictEqual(textHelperAsync, false, 'helper async text buffer should return false');

  const binaryAsync = await isBinaryFile(binaryBuffer, binaryBuffer.length);
  assert.strictEqual(binaryAsync, true, 'async binary buffer should return true');
  const binaryHelperAsync = await detectBinary(binaryBuffer, binaryBuffer.length);
  assert.strictEqual(binaryHelperAsync, true, 'helper async binary buffer should return true');

  // 3. File path detection (synchronous and asynchronous)
  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'isbin-contract-'));
  const textFilePath = path.join(tmpDir, 'sample-text.txt');
  const binaryFilePath = path.join(tmpDir, 'sample-binary.bin');

  try {
    fs.writeFileSync(textFilePath, 'Plain text content for file test.\nSecond line.\n');
    fs.writeFileSync(binaryFilePath, Buffer.from([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0x00, 0x00, 0x00]));

    // Sync file path
    assert.strictEqual(isBinaryFileSync(textFilePath), false, 'sync text file should return false');
    assert.strictEqual(detectBinarySync(textFilePath), false, 'helper sync text file should return false');
    assert.strictEqual(isBinaryFileSync(binaryFilePath), true, 'sync binary file should return true');
    assert.strictEqual(detectBinarySync(binaryFilePath), true, 'helper sync binary file should return true');

    // Async file path
    assert.strictEqual(await isBinaryFile(textFilePath), false, 'async text file should return false');
    assert.strictEqual(await detectBinary(textFilePath), false, 'helper async text file should return false');
    assert.strictEqual(await isBinaryFile(binaryFilePath), true, 'async binary file should return true');
    assert.strictEqual(await detectBinary(binaryFilePath), true, 'helper async binary file should return true');
  } finally {
    fs.rmSync(tmpDir, { recursive: true, force: true });
  }

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

runTests().catch((err) => {
  console.error(err);
  process.exit(1);
});