@types/js-yaml 4.0.9: dump

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 dump in pkg:npm/%40types/js-yaml@4.0.9
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40types/js-yaml@4.0.9
Demonstrate these symbols/APIs:
  - dump
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:52103b258a740e7067c800a3289edb87170eae0a8afd5445ce04995ffe4d6fb0","constraints":{"executionContext":"node"},"contract":["@types/js-yaml package.json declares type definitions entry point index.d.ts and version 4.0.9","@types/js-yaml index.d.ts exports dump function declaration accepting obj and optional DumpOptions returning string","@types/js-yaml index.d.ts declares DumpOptions interface with formatting and serialization options","@types/js-yaml DumpOptions supports sortKeys, lineWidth, noRefs, and noCompatMode options","@types/js-yaml DumpOptions supports condenseFlow, quotingType, forceQuotes, and replacer callback","@types/js-yaml index.d.mts re-exports dump function definitions for ESM imports"],"goal":"verify dump in pkg:npm/%40types/js-yaml@4.0.9","kind":"HOW","packages":["pkg:npm/%40types/js-yaml@4.0.9"],"schemaVersion":1,"symbols":["dump"]},"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/%40types/js-yaml@4.0.9"],"schemaVersion":1,"subject":"pkg:npm/%40types/js-yaml@4.0.9","symbols":["dump"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-types-js-yaml",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-types-js-yaml",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "@types/js-yaml": "4.0.9"
      }
    },
    "node_modules/@types/js-yaml": {
      "version": "4.0.9",
      "resolved": "https://registry.npmjs.org/@types/js-yaml/-/js-yaml-4.0.9.tgz",
      "integrity": "sha512-k4MGaQl5TGo/iipqb2UDG2UwjXziSWkh0uysQelTlJpX1qGlpUZYm8PnO4DxG1qBomtJUdYJ6qR6xdIah10JLg==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-types-js-yaml",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "@types/js-yaml": "4.0.9"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify dump in pkg:npm/%40types/js-yaml@4.0.9",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40types/js-yaml@4.0.9"
  ],
  "symbols": [
    "dump"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

import assert from 'node:assert/strict';
import fs from 'node:fs';
import path from 'node:path';
import { createRequire } from 'node:module';

const require = createRequire(import.meta.url);

// 1. @types/js-yaml package.json declares type definitions entry point index.d.ts and version 4.0.9
const pkgJsonPath = require.resolve('@types/js-yaml/package.json');
assert.ok(fs.existsSync(pkgJsonPath));
const pkgJson = JSON.parse(fs.readFileSync(pkgJsonPath, 'utf8'));
assert.equal(pkgJson.name, '@types/js-yaml');
assert.equal(pkgJson.version, '4.0.9');
assert.equal(pkgJson.types, 'index.d.ts');
assert.equal(pkgJson.exports['.'].types.import, './index.d.mts');
assert.equal(pkgJson.exports['.'].types.default, './index.d.ts');

const pkgDir = path.dirname(pkgJsonPath);

// 2. @types/js-yaml index.d.ts exports dump function declaration accepting obj and optional DumpOptions returning string
const dtsPath = path.join(pkgDir, 'index.d.ts');
assert.ok(fs.existsSync(dtsPath));
const dtsContent = fs.readFileSync(dtsPath, 'utf8');

assert.ok(dtsContent.includes('export function dump(obj: any, opts?: DumpOptions): string;'));

// 3. @types/js-yaml index.d.ts declares DumpOptions interface with formatting and serialization options
assert.ok(dtsContent.includes('export interface DumpOptions {'));
assert.ok(dtsContent.includes('indent?: number | undefined;'));
assert.ok(dtsContent.includes('noArrayIndent?: boolean | undefined;'));
assert.ok(dtsContent.includes('skipInvalid?: boolean | undefined;'));
assert.ok(dtsContent.includes('flowLevel?: number | undefined;'));

// 4. @types/js-yaml DumpOptions supports sortKeys, lineWidth, noRefs, and noCompatMode options
assert.ok(dtsContent.includes('sortKeys?: boolean | ((a: any, b: any) => number) | undefined;'));
assert.ok(dtsContent.includes('lineWidth?: number | undefined;'));
assert.ok(dtsContent.includes('noRefs?: boolean | undefined;'));
assert.ok(dtsContent.includes('noCompatMode?: boolean | undefined;'));

// 5. @types/js-yaml DumpOptions supports condenseFlow, quotingType, forceQuotes, and replacer callback
assert.ok(dtsContent.includes('condenseFlow?: boolean | undefined;'));
assert.ok(dtsContent.includes("quotingType?: \"'\" | \"\\\"\" | undefined;"));
assert.ok(dtsContent.includes('forceQuotes?: boolean | undefined;'));
assert.ok(dtsContent.includes('replacer?: ((key: string, value: any) => any) | undefined;'));

// 6. @types/js-yaml index.d.mts re-exports dump function definitions for ESM imports
const dtsMtsPath = path.join(pkgDir, 'index.d.mts');
assert.ok(fs.existsSync(dtsMtsPath));
const dtsMtsContent = fs.readFileSync(dtsMtsPath, 'utf8');
assert.ok(dtsMtsContent.includes('export * from "./index.js";'));

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