shebang-regex 3.0.0

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/shebang-regex@3.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/shebang-regex@3.0.0
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:sha256:5c88e6e0f33b558bbcfa1e506e8bf50f58b46164c091877611283c13cad75cc5","constraints":{"executionContext":"node"},"contract":["shebangRegex is a RegExp instance matching a shebang line starting with #!","isShebang returns true for standard env and binary shebang lines","isShebang returns false for strings without leading shebang or invalid inputs","isShebang does not match shebang lines that do not start at index 0","matchShebang extracts full shebang line and interpreter path","matchShebang captures interpreter arguments and options","matchShebang handles bare shebang #! with empty captured path","matchShebang returns null for non-matching or non-string inputs"],"goal":"verify pkg:npm/shebang-regex@3.0.0","kind":"HOW","packages":["pkg:npm/shebang-regex@3.0.0"],"schemaVersion":1},"contractCommand":["node","test/contract.mjs"],"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/shebang-regex@3.0.0"],"schemaVersion":1,"subject":"pkg:npm/shebang-regex@3.0.0","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-shebang-regex",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-shebang-regex",
      "version": "1.0.0",
      "dependencies": {
        "shebang-regex": "3.0.0"
      }
    },
    "node_modules/shebang-regex": {
      "version": "3.0.0",
      "resolved": "https://registry.npmjs.org/shebang-regex/-/shebang-regex-3.0.0.tgz",
      "integrity": "sha512-7++dFhtcx3353uBaq8DDR4NuxBetBzC7ZQOhmTQInHEd6bSrXdiEyzCvG07Z44UYdLShWUyXt5M/yhz8ekcb1A==",
      "license": "MIT",
      "engines": {
        "node": ">=8"
      }
    }
  }
}

{
  "name": "sample-shebang-regex",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification of shebang-regex",
  "main": "src/index.js",
  "dependencies": {
    "shebang-regex": "3.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/shebang-regex@3.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/shebang-regex@3.0.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

'use strict';

const shebangRegex = require('shebang-regex');

/**
 * Test whether a given string begins with a shebang line.
 * @param {string} string - Input string to test.
 * @returns {boolean} True if string begins with a shebang line, false otherwise.
 */
function isShebang(string) {
  if (typeof string !== 'string') {
    return false;
  }
  return shebangRegex.test(string);
}

/**
 * Match and extract shebang components from a given string.
 * @param {string} string - Input string.
 * @returns {{ full: string, path: string } | null} Shebang match object or null if not found.
 */
function matchShebang(string) {
  if (typeof string !== 'string') {
    return null;
  }
  const match = shebangRegex.exec(string);
  if (!match) {
    return null;
  }
  return {
    full: match[0],
    path: match[1]
  };
}

module.exports = {
  shebangRegex,
  isShebang,
  matchShebang
};

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

const require = createRequire(import.meta.url);
const { shebangRegex, isShebang, matchShebang } = require('../src/index.js');

// 1. shebangRegex is a RegExp instance matching a shebang line starting with #!
{
  assert.ok(shebangRegex instanceof RegExp);
  assert.equal(shebangRegex.source, '^#!(.*)');
}

// 2. isShebang returns true for standard env and binary shebang lines
{
  assert.equal(isShebang('#!/usr/bin/env node\nconsole.log(1);'), true);
  assert.equal(isShebang('#!/bin/bash\necho 1'), true);
  assert.equal(isShebang('#!/usr/bin/python3'), true);
}

// 3. isShebang returns false for strings without leading shebang or invalid inputs
{
  assert.equal(isShebang('console.log("hello");'), false);
  assert.equal(isShebang('// #!/usr/bin/env node'), false);
  assert.equal(isShebang('echo "#!/bin/sh"'), false);
  assert.equal(isShebang(''), false);
  assert.equal(isShebang(null), false);
  assert.equal(isShebang(undefined), false);
}

// 4. isShebang does not match shebang lines that do not start at index 0
{
  const multiline = 'const a = 1;\n#!/bin/sh';
  assert.equal(isShebang(multiline), false);
}

// 5. matchShebang extracts full shebang line and interpreter path
{
  const result = matchShebang('#!/usr/bin/env node\nconsole.log(1);');
  assert.ok(result);
  assert.equal(result.full, '#!/usr/bin/env node');
  assert.equal(result.path, '/usr/bin/env node');
}

// 6. matchShebang captures interpreter arguments and options
{
  const result = matchShebang('#!/usr/bin/env -S node --trace-warnings\nprocess.exit(0);');
  assert.ok(result);
  assert.equal(result.full, '#!/usr/bin/env -S node --trace-warnings');
  assert.equal(result.path, '/usr/bin/env -S node --trace-warnings');
}

// 7. matchShebang handles bare shebang #! with empty captured path
{
  const result = matchShebang('#!');
  assert.ok(result);
  assert.equal(result.full, '#!');
  assert.equal(result.path, '');
}

// 8. matchShebang returns null for non-matching or non-string inputs
{
  assert.equal(matchShebang('let x = 10;'), null);
  assert.equal(matchShebang(''), null);
  assert.equal(matchShebang(123), null);
}

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