shebang-regex 3.0.0: exec

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 shebang-regex.exec in pkg:npm/shebang-regex@3.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/shebang-regex@3.0.0
Demonstrate these symbols/APIs:
  - shebang-regex.exec
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:sha256:166d4449d643b3a42d312b94763a9e76e2f6e10470b83aeae2de934fd9734643","constraints":{"executionContext":"node"},"contract":["shebang-regex.exec matches standard shebang line and captures full line in index 0","shebang-regex.exec captures command path and arguments in index 1","shebang-regex.exec matches shebang with trailing options correctly","shebang-regex.exec captures empty string in index 1 when line only contains shebang prefix","shebang-regex.exec returns null when input string does not start with shebang","shebang-regex.exec returns null when input string is empty"],"goal":"verify shebang-regex.exec in pkg:npm/shebang-regex@3.0.0","kind":"HOW","packages":["pkg:npm/shebang-regex@3.0.0"],"schemaVersion":1,"symbols":["shebang-regex.exec"]},"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","symbols":["shebang-regex.exec"],"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",
      "license": "MIT-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 code sample for shebang-regex exec",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "shebang-regex": "3.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify shebang-regex.exec in pkg:npm/shebang-regex@3.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/shebang-regex@3.0.0"
  ],
  "symbols": [
    "shebang-regex.exec"
  ],
  "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');

module.exports = shebangRegex;

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

const require = createRequire(import.meta.url);
const shebangRegex = require('../src/index.js');

// 1. shebang-regex.exec matches standard shebang line and captures full line in index 0
const match1 = shebangRegex.exec('#!/usr/bin/env node\nconsole.log("hello");');
assert.notEqual(match1, null, 'shebangRegex.exec should return match for valid shebang line');
assert.equal(match1[0], '#!/usr/bin/env node', 'match[0] should be the full shebang line');

// 2. shebang-regex.exec captures command path and arguments in index 1
assert.equal(match1[1], '/usr/bin/env node', 'match[1] should capture the binary path');

// 3. shebang-regex.exec matches shebang with trailing options correctly
const match2 = shebangRegex.exec('#!/bin/sh -e -x\necho test');
assert.notEqual(match2, null, 'shebangRegex.exec should match shebang with options');
assert.equal(match2[0], '#!/bin/sh -e -x');
assert.equal(match2[1], '/bin/sh -e -x');

// 4. shebang-regex.exec captures empty string in index 1 when line only contains shebang prefix
const match3 = shebangRegex.exec('#!\n');
assert.notEqual(match3, null, 'shebangRegex.exec should match line with only shebang prefix');
assert.equal(match3[0], '#!');
assert.equal(match3[1], '');

// 5. shebang-regex.exec returns null when input string does not start with shebang
const nonShebang = 'console.log("hello");';
assert.equal(shebangRegex.exec(nonShebang), null, 'shebangRegex.exec should return null for non-shebang string');

const nonLeadingShebang = '\n#!/bin/bash';
assert.equal(shebangRegex.exec(nonLeadingShebang), null, 'shebangRegex.exec should return null when shebang is not at start of string');

// 6. shebang-regex.exec returns null when input string is empty
assert.equal(shebangRegex.exec(''), null, 'shebangRegex.exec should return null for empty string');

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