js-yaml 3.15.1: safeDump

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 js-yaml.safeDump in pkg:npm/js-yaml@3.15.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/js-yaml@3.15.1
Demonstrate these symbols/APIs:
  - js-yaml.safeDump

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:f1b5ca5134d6ba4b075a0793dc9697e599646c7d7da6b7cb9f3a33630c75cc77","contract":["yaml.safeDump serializes JavaScript objects and primitives into valid YAML strings using safe schema","yaml.safeDump supports formatting options including indent and sortKeys","yaml.safeDump supports flowLevel option to serialize collections in flow style","yaml.safeDump supports skipInvalid option to ignore functions without throwing","yaml.safeDump throws YAMLException when serializing functions by default","yaml.safeDump and yaml.safeLoad round-trip preserves nested objects and arrays"],"goal":"verify js-yaml.safeDump in pkg:npm/js-yaml@3.15.1","kind":"HOW","packages":["pkg:npm/js-yaml@3.15.1"],"schemaVersion":1,"symbols":["js-yaml.safeDump"]},"contractCommand":["node","test/contract.cjs"],"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/js-yaml@3.15.1"],"schemaVersion":1,"subject":"pkg:npm/js-yaml@3.15.1","symbols":["js-yaml.safeDump"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-js-yaml-safedump",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-js-yaml-safedump",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "js-yaml": "3.15.1"
      }
    },
    "node_modules/argparse": {
      "version": "1.0.10",
      "resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
      "integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
      "license": "MIT",
      "dependencies": {
        "sprintf-js": "~1.0.2"
      }
    },
    "node_modules/esprima": {
      "version": "4.0.1",
      "resolved": "https://registry.npmjs.org/esprima/-/esprima-4.0.1.tgz",
      "integrity": "sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A==",
      "license": "BSD-2-Clause",
      "bin": {
        "esparse": "bin/esparse.js",
        "esvalidate": "bin/esvalidate.js"
      },
      "engines": {
        "node": ">=4"
      }
    },
    "node_modules/js-yaml": {
      "version": "3.15.1",
      "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.15.1.tgz",
      "integrity": "sha512-S99WuO3HlhO3XN41EtYUNl9zzXjoJx7QvmipxsJVxtCBT0YHEFy+iOJhjSvrmV12nYhWpZaM8lPHkJm0yUMbag==",
      "license": "MIT",
      "dependencies": {
        "argparse": "^1.0.7",
        "esprima": "^4.0.0"
      },
      "bin": {
        "js-yaml": "bin/js-yaml.js"
      }
    },
    "node_modules/sprintf-js": {
      "version": "1.0.3",
      "resolved": "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.0.3.tgz",
      "integrity": "sha512-D9cPgkvLlV3t3IzL0D0YLvGA9Ahk4PcvVwUbN0dSGr1aP0Nrt4AEnTUbuGvquEC0mA64Gqt1fzirlRs5ibXx8g==",
      "license": "BSD-3-Clause"
    }
  }
}

{
  "name": "sample-js-yaml-safedump",
  "version": "1.0.0",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "js-yaml": "3.15.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify js-yaml.safeDump in pkg:npm/js-yaml@3.15.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/js-yaml@3.15.1"
  ],
  "symbols": [
    "js-yaml.safeDump"
  ]
}

const assert = require('node:assert');
const yaml = require('js-yaml');

// 1. yaml.safeDump serializes JavaScript objects and primitives into valid YAML strings using safe schema
const data = {
  name: 'CodeSampleX',
  version: 1,
  enabled: true,
  tags: ['test', 'node']
};
const yamlStr = yaml.safeDump(data);
assert.strictEqual(typeof yamlStr, 'string');
assert.ok(yamlStr.includes('name: CodeSampleX'));
assert.ok(yamlStr.includes('version: 1'));
assert.ok(yamlStr.includes('enabled: true'));
assert.ok(yamlStr.includes('- test'));

// 2. yaml.safeDump supports formatting options including indent and sortKeys
const unsorted = { z: 1, a: 2, m: 3 };
const formatted = yaml.safeDump(unsorted, { sortKeys: true, indent: 4 });
assert.strictEqual(formatted, 'a: 2\nm: 3\nz: 1\n');

// 3. yaml.safeDump supports flowLevel option to serialize collections in flow style
const flowData = { items: [1, 2, 3] };
const flowYaml = yaml.safeDump(flowData, { flowLevel: 1 });
assert.ok(flowYaml.includes('[1, 2, 3]'));

// 4. yaml.safeDump supports skipInvalid option to ignore functions without throwing
const objWithFn = {
  valid: 'hello',
  invalidFn: () => 'skip me'
};
const skippedYaml = yaml.safeDump(objWithFn, { skipInvalid: true });
assert.ok(skippedYaml.includes('valid: hello'));
assert.ok(!skippedYaml.includes('invalidFn'));

// 5. yaml.safeDump throws YAMLException when serializing functions by default
assert.throws(() => {
  yaml.safeDump({ fn: () => {} });
}, yaml.YAMLException);

// 6. yaml.safeDump and yaml.safeLoad round-trip preserves nested objects and arrays
const complex = {
  project: 'sample-project',
  numbers: [10, 20, 30],
  meta: {
    active: true,
    count: 42,
    ratio: 3.14
  }
};
const roundTrip = yaml.safeLoad(yaml.safeDump(complex));
assert.deepStrictEqual(roundTrip, complex);

console.log('Contract passed');