pathe 2.0.3: extname

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 pathe.extname in pkg:npm/pathe@2.0.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/pathe@2.0.3
Demonstrate these symbols/APIs:
  - pathe.extname

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:ebf6bed69c2bbb8521c94bba87070b319824c940272ced5cbf999cb39804690f","contract":["extname returns the extension from the last dot in standard filenames","extname returns the last extension for multi-extension filenames","extname extracts extension from paths with POSIX and Windows directory separators","extname handles dotfiles returning empty string when dot is only the leading character","extname handles trailing dots and special path components","extname handles undefined or null by returning an empty string and throws TypeError for non-string inputs","extname is exported as a function and available on posix and win32 sub-namespaces"],"goal":"verify pathe.extname in pkg:npm/pathe@2.0.3","kind":"HOW","packages":["pkg:npm/pathe@2.0.3"],"schemaVersion":1,"symbols":["pathe.extname"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/pathe@2.0.3"],"schemaVersion":1,"subject":"pkg:npm/pathe@2.0.3","symbols":["pathe.extname"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-pathe-extname",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-pathe-extname",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "pathe": "2.0.3"
      }
    },
    "node_modules/pathe": {
      "version": "2.0.3",
      "resolved": "https://registry.npmjs.org/pathe/-/pathe-2.0.3.tgz",
      "integrity": "sha512-WUjGcAqP1gQacoQe+OBJsFA7Ld4DyXuUIjZ5cc75cLHvJ7dtNsTugphxIADwspS+AraAUePCKrSVtPLFj/F88w==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-pathe-extname",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room code sample for pathe.extname in pathe@2.0.3",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "pathe": "2.0.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pathe.extname in pkg:npm/pathe@2.0.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/pathe@2.0.3"
  ],
  "symbols": [
    "pathe.extname"
  ]
}

'use strict';

const pathe = require('pathe');

/**
 * Returns the extension of the path.
 *
 * @param {string} path - The path to evaluate.
 * @returns {string} The file extension or empty string.
 */
function getExtname(path) {
  return pathe.extname(path);
}

module.exports = {
  pathe,
  extname: pathe.extname,
  getExtname
};

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

const require = createRequire(import.meta.url);
const { pathe, extname, getExtname } = require('../src/index.js');

async function testAll() {
  // 1. extname returns the extension from the last dot in standard filenames
  assert.equal(extname('index.html'), '.html', 'extname should extract .html');
  assert.equal(extname('styles.css'), '.css', 'extname should extract .css');
  assert.equal(getExtname('script.js'), '.js', 'getExtname helper should extract .js');

  // 2. extname returns the last extension for multi-extension filenames
  assert.equal(extname('archive.tar.gz'), '.gz', 'extname should extract .gz from tar.gz');
  assert.equal(extname('app.test.ts'), '.ts', 'extname should extract .ts from test.ts');
  assert.equal(extname('index.coffee.md'), '.md', 'extname should extract .md');

  // 3. extname extracts extension from paths with POSIX and Windows directory separators
  assert.equal(extname('nested/path/to/component.vue'), '.vue', 'extname should handle posix path');
  assert.equal(extname('windows\\folder\\subfolder\\file.json'), '.json', 'extname should handle Windows backslash path');
  assert.equal(extname('mixed/dir\\subfolder\\script.min.js'), '.js', 'extname should handle mixed separators');

  // 4. extname handles dotfiles returning empty string when dot is only the leading character
  assert.equal(extname('.gitignore'), '', 'dotfile without other extension should return empty string');
  assert.equal(extname('.env'), '', '.env should return empty string');
  assert.equal(extname('.bashrc.backup'), '.backup', '.bashrc.backup should return .backup');

  // 5. extname handles trailing dots and special path components
  assert.equal(extname('file.'), '.', 'trailing dot should return dot');
  assert.equal(extname('..'), '', '.. should return empty string');
  assert.equal(extname('...'), '.', '... should return dot');
  assert.equal(extname('filename'), '', 'file without extension should return empty string');
  assert.equal(extname(''), '', 'empty string should return empty string');

  // 6. extname handles undefined or null by returning an empty string and throws TypeError for non-string inputs
  assert.equal(extname(undefined), '', 'undefined should return empty string');
  assert.equal(extname(null), '', 'null should return empty string');
  assert.throws(
    () => extname(123),
    {
      name: 'TypeError'
    },
    'non-string argument should throw TypeError'
  );

  // 7. extname is exported as a function and available on posix and win32 sub-namespaces
  assert.equal(typeof extname, 'function', 'extname must be a function');
  assert.equal(typeof pathe.extname, 'function', 'pathe.extname must be a function');
  assert.equal(pathe.posix.extname('posix/sub/file.txt'), '.txt', 'pathe.posix.extname should return .txt');
  assert.equal(pathe.win32.extname('win32\\sub\\file.txt'), '.txt', 'pathe.win32.extname should return .txt');

  console.log('All contract assertions for pathe.extname passed successfully.');
}

testAll().catch((err) => {
  console.error('Contract test failure:', err);
  process.exit(1);
});