sanitize-filename 1.6.4: sanitize

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 sanitize in pkg:npm/sanitize-filename@1.6.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/sanitize-filename@1.6.4
Demonstrate these symbols/APIs:
  - sanitize

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:ad5d5e2fe766105b34e4e48c10558a67e92ebfa009c07507e4acc7c8790b79d3","contract":["sanitize removes illegal filename characters including slashes, colons, angle brackets, and question marks","sanitize replaces illegal characters with a custom replacement string when specified in options","sanitize replaces illegal characters dynamically using a custom replacement function","sanitize removes Windows reserved filenames such as COM1, AUX, and NUL","sanitize strips trailing dots and spaces that are invalid on Windows filesystems","sanitize truncates filenames exceeding 255 bytes to 255 bytes using UTF-8 aware truncation","sanitize leaves already valid filenames unchanged","sanitize throws an Error when passed a non-string input"],"goal":"verify sanitize in pkg:npm/sanitize-filename@1.6.4","kind":"HOW","packages":["pkg:npm/sanitize-filename@1.6.4"],"schemaVersion":1,"symbols":["sanitize"]},"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/sanitize-filename@1.6.4"],"schemaVersion":1,"subject":"pkg:npm/sanitize-filename@1.6.4","symbols":["sanitize"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-sanitize-filename",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-sanitize-filename",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "sanitize-filename": "1.6.4"
      }
    },
    "node_modules/sanitize-filename": {
      "version": "1.6.4",
      "resolved": "https://registry.npmjs.org/sanitize-filename/-/sanitize-filename-1.6.4.tgz",
      "integrity": "sha512-9ZyI08PsvdQl2r/bBIGubpVdR3RR9sY6RDiWFPreA21C/EFlQhmgo20UZlNjZMMZNubusLhAQozkA0Od5J21Eg==",
      "license": "WTFPL OR ISC",
      "dependencies": {
        "truncate-utf8-bytes": "^1.0.0"
      }
    },
    "node_modules/truncate-utf8-bytes": {
      "version": "1.0.2",
      "resolved": "https://registry.npmjs.org/truncate-utf8-bytes/-/truncate-utf8-bytes-1.0.2.tgz",
      "integrity": "sha512-95Pu1QXQvruGEhv62XCMO3Mm90GscOCClvrIUwCM0PYOXK3kaF3l3sIHxx71ThJfcbM2O5Au6SO3AWCSEfW4mQ==",
      "license": "WTFPL",
      "dependencies": {
        "utf8-byte-length": "^1.0.1"
      }
    },
    "node_modules/utf8-byte-length": {
      "version": "1.0.5",
      "resolved": "https://registry.npmjs.org/utf8-byte-length/-/utf8-byte-length-1.0.5.tgz",
      "integrity": "sha512-Xn0w3MtiQ6zoz2vFyUVruaCL53O/DwUvkEeOvj+uulMm0BkUGYWmBYVyElqZaSLhY6ZD0ulfU3aBra2aVT4xfA==",
      "license": "(WTFPL OR MIT)"
    }
  }
}

{
  "name": "sample-sanitize-filename",
  "version": "1.0.0",
  "private": true,
  "description": "verify sanitize in pkg:npm/sanitize-filename@1.6.4",
  "main": "src/index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "sanitize-filename": "1.6.4"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "verify sanitize in pkg:npm/sanitize-filename@1.6.4",
  "kind": "HOW",
  "packages": [
    "pkg:npm/sanitize-filename@1.6.4"
  ],
  "symbols": [
    "sanitize"
  ]
}

'use strict';

const sanitize = require('sanitize-filename');

/**
 * Sanitizes a string to make it safe for use as a filename.
 * @param {string} input - The input string to sanitize.
 * @param {object} [options={}] - Options object for sanitization.
 * @param {string|Function} [options.replacement=""] - Replacement for invalid characters.
 * @returns {string} Sanitized filename string.
 */
function sanitizeFileName(input, options = {}) {
  return sanitize(input, options);
}

module.exports = {
  sanitize,
  sanitizeFileName,
};

'use strict';

const assert = require('node:assert/strict');
const { sanitize, sanitizeFileName } = require('../src/index.js');

// 1. sanitize removes illegal filename characters including slashes, colons, angle brackets, and question marks
{
  const input = 'report/2026:09<draft>?v1*bar|qux"test.pdf';
  const result = sanitize(input);
  assert.equal(result, 'report202609draftv1barquxtest.pdf');

  const helperResult = sanitizeFileName('hello/world\\test');
  assert.equal(helperResult, 'helloworldtest');
}

// 2. sanitize replaces illegal characters with a custom replacement string when specified in options
{
  const input = 'foo/bar:baz?qux';
  const result = sanitize(input, { replacement: '_' });
  assert.equal(result, 'foo_bar_baz_qux');

  const hyphenResult = sanitizeFileName('chapter:1/intro', { replacement: '-' });
  assert.equal(hyphenResult, 'chapter-1-intro');
}

// 3. sanitize replaces illegal characters dynamically using a custom replacement function
{
  const input = 'a/b:c';
  const result = sanitize(input, {
    replacement: (match) => (match === '/' ? '-' : '_'),
  });
  assert.equal(result, 'a-b_c');
}

// 4. sanitize removes Windows reserved filenames such as COM1, AUX, and NUL
{
  assert.equal(sanitize('COM1'), '');
  assert.equal(sanitize('aux.txt'), '');
  assert.equal(sanitize('NUL'), '');
  assert.equal(sanitize('prn.dat'), '');
  assert.equal(sanitize('lpt1.log'), '');
}

// 5. sanitize strips trailing dots and spaces that are invalid on Windows filesystems
{
  assert.equal(sanitize('filename...'), 'filename');
  assert.equal(sanitize('filename   '), 'filename');
  assert.equal(sanitize('filename. . .'), 'filename');
}

// 6. sanitize truncates filenames exceeding 255 bytes to 255 bytes using UTF-8 aware truncation
{
  const longName = 'a'.repeat(300);
  const result = sanitize(longName);
  assert.equal(result.length, 255);
  assert.equal(result, 'a'.repeat(255));

  // Multi-byte UTF-8 characters
  const multiByte = '한'.repeat(100); // each '한' is 3 bytes (300 bytes total)
  const multiByteResult = sanitize(multiByte);
  const byteLength = Buffer.byteLength(multiByteResult, 'utf8');
  assert.ok(byteLength <= 255, 'Truncated byte length should not exceed 255');
  assert.equal(byteLength, 255);
  assert.equal(multiByteResult.length, 85); // 85 * 3 = 255 bytes
}

// 7. sanitize leaves already valid filenames unchanged
{
  const valid = 'my-valid_filename.123.tar.gz';
  assert.equal(sanitize(valid), valid);
  assert.equal(sanitizeFileName('document.pdf'), 'document.pdf');
}

// 8. sanitize throws an Error when passed a non-string input
{
  assert.throws(
    () => {
      sanitize(12345);
    },
    {
      name: 'Error',
      message: 'Input must be string',
    },
    'Should throw when passed a number'
  );

  assert.throws(
    () => {
      sanitize(null);
    },
    {
      name: 'Error',
      message: 'Input must be string',
    },
    'Should throw when passed null'
  );

  assert.throws(
    () => {
      sanitize(undefined);
    },
    {
      name: 'Error',
      message: 'Input must be string',
    },
    'Should throw when passed undefined'
  );

  assert.throws(
    () => {
      sanitize({});
    },
    {
      name: 'Error',
      message: 'Input must be string',
    },
    'Should throw when passed an object'
  );
}