yaml 2.9.1: parse

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.parse 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.parse

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:c1452cc33e3e0b3455c0dbe3646ed243e4607e21c296cf307419ba1a25b3cc14","constraints":{"executionContext":"node"},"contract":["yaml.parse parses scalar YAML values into JavaScript primitives","yaml.parse parses nested YAML mappings and sequences into JavaScript objects and arrays","yaml.parse transforms values using an optional reviver function","yaml.parse throws an error on invalid YAML syntax"],"goal":"verify yaml.parse in pkg:npm/yaml@2.9.1","kind":"HOW","packages":["pkg:npm/yaml@2.9.1"],"schemaVersion":1,"symbols":["yaml.parse"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","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.parse"],"verifierAdapter":"node-typescript@1"}

const YAML = require('yaml');

/**
 * Parse a YAML string into a JavaScript value.
 * @param {string} text
 * @param {Function|object} [reviver]
 * @returns {any}
 */
function parseYaml(text, reviver) {
  return YAML.parse(text, reviver);
}

module.exports = {
  parseYaml,
  YAML,
};

{
  "name": "sample-yaml",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-yaml",
      "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",
  "version": "1.0.0",
  "description": "verify yaml.parse in pkg:npm/yaml@2.9.1",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "yaml": "2.9.1"
  }
}

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

import assert from 'node:assert/strict';
import YAML from 'yaml';
import pkg from '../index.js';

const { parseYaml } = pkg;

// 1. yaml.parse parses scalar YAML values into JavaScript primitives
{
  assert.equal(parseYaml('42'), 42);
  assert.equal(parseYaml('3.14159'), 3.14159);
  assert.equal(parseYaml('hello world'), 'hello world');
  assert.equal(parseYaml('true'), true);
  assert.equal(parseYaml('false'), false);
  assert.equal(parseYaml('null'), null);
}

// 2. yaml.parse parses nested YAML mappings and sequences into JavaScript objects and arrays
{
  const yamlText = `
name: sample
version: 1.0.0
items:
  - alpha
  - beta
config:
  active: true
  retries: 5
`;
  const result = parseYaml(yamlText);
  assert.deepEqual(result, {
    name: 'sample',
    version: '1.0.0',
    items: ['alpha', 'beta'],
    config: {
      active: true,
      retries: 5
    }
  });
}

// 3. yaml.parse transforms values using an optional reviver function
{
  const yamlText = `
count: 10
multiplier: 2
`;
  const result = YAML.parse(yamlText, (key, value) => {
    if (typeof value === 'number') {
      return value * 10;
    }
    return value;
  });
  assert.deepEqual(result, {
    count: 100,
    multiplier: 20
  });
}

// 4. yaml.parse throws an error on invalid YAML syntax
{
  const invalidYaml = `
unclosed_list: [1, 2,
invalid_map: {key
`;
  assert.throws(
    () => {
      parseYaml(invalidYaml);
    },
    (err) => err instanceof Error
  );
}

console.log('Contract passed');