yaml 2.9.1: stringify

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 yaml.stringify in pkg:npm/yaml@2.9.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/yaml@2.9.1
Demonstrate these symbols/APIs:
  - yaml.stringify

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:sha256:125a9bbd672a2064c302e5bf0a67a05b0a8cb5492eb8c9d6f98f535ae74a91dd","contract":["yaml.stringify serializes JavaScript objects into formatted YAML strings","yaml.stringify serializes arrays and primitive values to YAML strings","yaml.stringify handles nested objects and collections","yaml.stringify supports replacer functions for transforming or filtering values","yaml.stringify respects custom formatting options like indent"],"goal":"verify yaml.stringify in pkg:npm/yaml@2.9.1","kind":"HOW","packages":["pkg:npm/yaml@2.9.1"],"schemaVersion":1,"symbols":["yaml.stringify"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/yaml@2.9.1"],"schemaVersion":1,"subject":"pkg:npm/yaml@2.9.1","symbols":["yaml.stringify"],"verifierAdapter":"node-typescript@1"}

import YAML from 'yaml';

/**
 * Serializes a JavaScript value to a YAML string.
 *
 * @param {any} value - The value to stringify.
 * @param {Function|Array} [replacer] - Replacer function or array of property keys.
 * @param {object|number|string} [options] - Stringify options or indentation length/string.
 * @returns {string} The formatted YAML string.
 */
export function stringifyYaml(value, replacer, options) {
  return YAML.stringify(value, replacer, options);
}

export { YAML };
export default YAML;

{
  "name": "sample-yaml-stringify",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-yaml-stringify",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "yaml": "2.9.1"
      }
    },
    "node_modules/yaml": {
      "version": "2.9.1",
      "resolved": "https://registry.npmjs.org/yaml/-/yaml-2.9.1.tgz",
      "integrity": "sha512-3NxN8+78OdzbT7C/WjGsyfPAtJaN3FNDsWxv7Y7mcDsT/oOmgW8BpyQQFFBnvZE3j9Y2Sdz1ULFLezL7Eb2yFw==",
      "license": "ISC",
      "bin": {
        "yaml": "bin.mjs"
      },
      "engines": {
        "node": ">= 14.6"
      },
      "funding": {
        "url": "https://github.com/sponsors/eemeli"
      }
    }
  }
}

{
  "name": "sample-yaml-stringify",
  "version": "1.0.0",
  "description": "verify yaml.stringify in pkg:npm/yaml@2.9.1",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "yaml": "2.9.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify yaml.stringify in pkg:npm/yaml@2.9.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/yaml@2.9.1"
  ],
  "symbols": [
    "yaml.stringify"
  ]
}

import assert from 'node:assert/strict';
import YAML from 'yaml';
import { stringifyYaml } from '../index.mjs';

// 1. yaml.stringify serializes JavaScript objects into formatted YAML strings
{
  const obj = { title: 'CodeSampleX', count: 42, active: true };
  const expected = 'title: CodeSampleX\ncount: 42\nactive: true\n';
  assert.strictEqual(YAML.stringify(obj), expected);
  assert.strictEqual(stringifyYaml(obj), expected);
}

// 2. yaml.stringify serializes arrays and primitive values to YAML strings
{
  const arr = ['alpha', 'beta', 'gamma'];
  const expectedArr = '- alpha\n- beta\n- gamma\n';
  assert.strictEqual(YAML.stringify(arr), expectedArr);

  assert.strictEqual(YAML.stringify('hello world'), 'hello world\n');
  assert.strictEqual(YAML.stringify(100), '100\n');
  assert.strictEqual(YAML.stringify(true), 'true\n');
}

// 3. yaml.stringify handles nested objects and collections
{
  const nested = {
    app: {
      name: 'worker',
      config: {
        timeout: 5000,
        tags: ['linux', 'node']
      }
    }
  };
  const yamlOut = YAML.stringify(nested);
  const parsed = YAML.parse(yamlOut);
  assert.deepStrictEqual(parsed, nested);
}

// 4. yaml.stringify supports replacer functions for transforming or filtering values
{
  const data = {
    user: 'alice',
    secret: 'hidden',
    score: 10
  };
  const result = YAML.stringify(data, (key, value) => {
    if (key === 'secret') return undefined;
    if (typeof value === 'number') return value * 2;
    return value;
  });
  assert.strictEqual(result, 'user: alice\nscore: 20\n');
}

// 5. yaml.stringify respects custom formatting options like indent
{
  const items = { list: ['one', 'two'] };
  const formatted = YAML.stringify(items, { indent: 4 });
  assert.strictEqual(formatted, 'list:\n    - one\n    - two\n');
}

console.log('PASS: All yaml.stringify contract assertions passed.');