cookie 1.1.1: stringifyCookie

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 cookie.stringifyCookie in pkg:npm/cookie@1.1.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/cookie@1.1.1
Demonstrate these symbols/APIs:
  - cookie.stringifyCookie

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:sha256:189dd4112e059327ff6c34f11d4e8202d7c879ac0d68504e05cd018f6dbe6379","contract":["cookie.stringifyCookie serializes key-value dictionary objects into Cookie header strings separated by semicolons","cookie.stringifyCookie URL-encodes values using encodeURIComponent by default","cookie.stringifyCookie supports a custom encode option function","cookie.stringifyCookie skips undefined property values","cookie.stringifyCookie throws TypeError when cookie name contains invalid characters","cookie.stringifyCookie throws TypeError when encoded cookie value contains invalid characters"],"goal":"verify cookie.stringifyCookie in pkg:npm/cookie@1.1.1","kind":"HOW","packages":["pkg:npm/cookie@1.1.1"],"schemaVersion":1,"symbols":["cookie.stringifyCookie"]},"contractCommand":["node","test/contract.mjs"],"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/cookie@1.1.1"],"schemaVersion":1,"subject":"pkg:npm/cookie@1.1.1","symbols":["cookie.stringifyCookie"],"verifierAdapter":"node-typescript@1"}

const cookie = require('cookie');

/**
 * Serializes key-value pairs into a Cookie header string.
 *
 * @param {Record<string, string | number | boolean>} cookies - Key-value dictionary.
 * @param {Object} [options] - Optional serialization options.
 * @param {function(string): string} [options.encode] - Custom encoder function.
 * @returns {string} Semicolon-separated Cookie header string.
 */
function stringifyCookieHeader(cookies, options) {
  return cookie.stringifyCookie(cookies, options);
}

module.exports = {
  stringifyCookieHeader,
  stringifyCookie: cookie.stringifyCookie
};

{
  "name": "sample-cookie-stringify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-cookie-stringify",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "cookie": "1.1.1"
      }
    },
    "node_modules/cookie": {
      "version": "1.1.1",
      "resolved": "https://registry.npmjs.org/cookie/-/cookie-1.1.1.tgz",
      "integrity": "sha512-ei8Aos7ja0weRpFzJnEA9UHJ/7XQmqglbRwnf2ATjcB9Wq874VKH9kfjjirM6UhU2/E5fFYadylyhFldcqSidQ==",
      "license": "MIT",
      "engines": {
        "node": ">=18"
      },
      "funding": {
        "type": "opencollective",
        "url": "https://opencollective.com/express"
      }
    }
  }
}

{
  "name": "sample-cookie-stringify",
  "version": "1.0.0",
  "description": "Clean-room verification sample for cookie.stringifyCookie",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "cookie": "1.1.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify cookie.stringifyCookie in pkg:npm/cookie@1.1.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/cookie@1.1.1"
  ],
  "symbols": [
    "cookie.stringifyCookie"
  ]
}

import assert from 'node:assert';
import cookie from 'cookie';
import { stringifyCookieHeader, stringifyCookie } from '../index.js';

// 1. cookie.stringifyCookie serializes key-value dictionary objects into Cookie header strings separated by semicolons
const basicCookies = { id: '123', session: 'xyz' };
const serialized = cookie.stringifyCookie(basicCookies);
assert.strictEqual(
  serialized,
  'id=123; session=xyz',
  'cookie.stringifyCookie serializes key-value dictionary objects into Cookie header strings separated by semicolons'
);
assert.strictEqual(
  stringifyCookieHeader(basicCookies),
  'id=123; session=xyz',
  'helper stringifyCookieHeader matches direct cookie.stringifyCookie call'
);
assert.strictEqual(
  stringifyCookie(basicCookies),
  'id=123; session=xyz',
  'named export stringifyCookie matches direct call'
);

// 2. cookie.stringifyCookie URL-encodes values using encodeURIComponent by default
const encodedCookies = { msg: 'hello world', tag: 'a&b' };
assert.strictEqual(
  cookie.stringifyCookie(encodedCookies),
  'msg=hello%20world; tag=a%26b',
  'cookie.stringifyCookie URL-encodes values using encodeURIComponent by default'
);

// 3. cookie.stringifyCookie supports a custom encode option function
const customEncoded = cookie.stringifyCookie(
  { token: 'abc' },
  { encode: (v) => v.toUpperCase() }
);
assert.strictEqual(
  customEncoded,
  'token=ABC',
  'cookie.stringifyCookie supports a custom encode option function'
);

// 4. cookie.stringifyCookie skips undefined property values
const withUndefined = { first: '1', skipped: undefined, third: '3' };
assert.strictEqual(
  cookie.stringifyCookie(withUndefined),
  'first=1; third=3',
  'cookie.stringifyCookie skips undefined property values'
);

// 5. cookie.stringifyCookie throws TypeError when cookie name contains invalid characters
assert.throws(
  () => cookie.stringifyCookie({ 'invalid name': 'val' }),
  {
    name: 'TypeError',
    message: 'cookie name is invalid: invalid name'
  },
  'cookie.stringifyCookie throws TypeError when cookie name contains invalid characters'
);

// 6. cookie.stringifyCookie throws TypeError when encoded cookie value contains invalid characters
assert.throws(
  () => cookie.stringifyCookie({ key: 'invalid;val' }, { encode: (v) => v }),
  {
    name: 'TypeError',
    message: 'cookie val is invalid: invalid;val'
  },
  'cookie.stringifyCookie throws TypeError when encoded cookie value contains invalid characters'
);

console.log('All contract assertions passed.');