media-typer 1.1.1: mediaTyper.format, mediaTyper.parse, mediaTyper.test

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 pkg:npm/media-typer@1.1.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/media-typer@1.1.1
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@11.8.0
  - runtime: node@24.13.1

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:c24b3ef76622798d08ef84061e83f995ba80101e09b7f9654eb5bb45b9ea7411","constraints":{"executionContext":"node"},"contract":["mediaTyper.parse parses valid media type strings into type, subtype, and optional suffix","mediaTyper.format formats media type descriptor objects into RFC 6838 media type strings","mediaTyper.test validates whether a string conforms to RFC 6838 media type syntax","mediaTyper.parse and mediaTyper.format throw TypeError on invalid input values"],"goal":"verify pkg:npm/media-typer@1.1.1","kind":"HOW","packages":["pkg:npm/media-typer@1.1.1"],"schemaVersion":1,"symbols":["mediaTyper.format","mediaTyper.parse","mediaTyper.test"]},"contractCommand":["node","test/contract.js"],"environment":{"arch":"x64","ecosystem":"npm","os":"windows","osVersionBucket":"11","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/media-typer@1.1.1"],"schemaVersion":1,"symbols":["mediaTyper.format","mediaTyper.parse","mediaTyper.test"],"verifierAdapter":"node-typescript@1"}

const mediaTyper = require('media-typer');

/**
 * Parse media type string into an object containing type, subtype, and suffix.
 * @param {string} string
 * @returns {{ type: string, subtype: string, suffix?: string }}
 */
function parseMediaType(string) {
  return mediaTyper.parse(string);
}

/**
 * Format media type object into a media type string.
 * @param {{ type: string, subtype: string, suffix?: string }} obj
 * @returns {string}
 */
function formatMediaType(obj) {
  return mediaTyper.format(obj);
}

/**
 * Test if a string is a valid media type.
 * @param {string} string
 * @returns {boolean}
 */
function testMediaType(string) {
  return mediaTyper.test(string);
}

module.exports = {
  parseMediaType,
  formatMediaType,
  testMediaType
};

{
  "name": "sample",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample",
      "version": "1.0.0",
      "dependencies": {
        "media-typer": "1.1.1"
      }
    },
    "node_modules/media-typer": {
      "version": "1.1.1",
      "resolved": "https://registry.npmjs.org/media-typer/-/media-typer-1.1.1.tgz",
      "integrity": "sha512-yz3xRaG20c6/BOzvYoDaGtPmGscs7YivItZEEqe6GbwNfHuxu9YNmvnEkMzKldAGY4/80pRcQRZSEnhquk9XuQ==",
      "license": "MIT",
      "engines": {
        "node": ">= 0.8"
      },
      "funding": {
        "type": "opencollective",
        "url": "https://opencollective.com/express"
      }
    }
  }
}

{
  "name": "sample",
  "version": "1.0.0",
  "dependencies": {
    "media-typer": "1.1.1"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/media-typer@1.1.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/media-typer@1.1.1"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@11.8.0",
    "runtime": "node@24.13.1"
  }
}

const assert = require('node:assert/strict');
const mediaTyper = require('media-typer');
const { parseMediaType, formatMediaType, testMediaType } = require('../index.js');

// Contract 1: mediaTyper.parse parses valid media type strings into type, subtype, and optional suffix
{
  const parsed1 = parseMediaType('application/json');
  assert.equal(parsed1.type, 'application');
  assert.equal(parsed1.subtype, 'json');
  assert.equal(parsed1.suffix, undefined);

  const parsed2 = parseMediaType('application/vnd.api+json');
  assert.equal(parsed2.type, 'application');
  assert.equal(parsed2.subtype, 'vnd.api');
  assert.equal(parsed2.suffix, 'json');

  const parsed3 = parseMediaType('image/svg+xml');
  assert.equal(parsed3.type, 'image');
  assert.equal(parsed3.subtype, 'svg');
  assert.equal(parsed3.suffix, 'xml');

  const parsedDirect = mediaTyper.parse('text/html');
  assert.equal(parsedDirect.type, 'text');
  assert.equal(parsedDirect.subtype, 'html');
  assert.equal(parsedDirect.suffix, undefined);
}

// Contract 2: mediaTyper.format formats media type descriptor objects into RFC 6838 media type strings
{
  const formatted1 = formatMediaType({ type: 'application', subtype: 'json' });
  assert.equal(formatted1, 'application/json');

  const formatted2 = formatMediaType({ type: 'application', subtype: 'vnd.api', suffix: 'json' });
  assert.equal(formatted2, 'application/vnd.api+json');

  const formatted3 = formatMediaType({ type: 'image', subtype: 'svg', suffix: 'xml' });
  assert.equal(formatted3, 'image/svg+xml');

  const formattedDirect = mediaTyper.format({ type: 'text', subtype: 'plain' });
  assert.equal(formattedDirect, 'text/plain');
}

// Contract 3: mediaTyper.test validates whether a string conforms to RFC 6838 media type syntax
{
  assert.equal(testMediaType('application/json'), true);
  assert.equal(testMediaType('application/vnd.api+json'), true);
  assert.equal(testMediaType('text/html'), true);
  assert.equal(testMediaType('invalid media type'), false);
  assert.equal(testMediaType('application/'), false);
  assert.equal(testMediaType('/json'), false);
  assert.equal(mediaTyper.test('image/png'), true);
  assert.equal(mediaTyper.test('not-a-media-type'), false);
}

// Contract 4: mediaTyper.parse and mediaTyper.format throw TypeError on invalid input values
{
  assert.throws(() => parseMediaType('invalid-media-type'), TypeError);
  assert.throws(() => parseMediaType(null), TypeError);
  assert.throws(() => parseMediaType(123), TypeError);

  assert.throws(() => formatMediaType(null), TypeError);
  assert.throws(() => formatMediaType({ type: 'invalid type', subtype: 'json' }), TypeError);
  assert.throws(() => formatMediaType({ type: 'application', subtype: 'invalid/subtype' }), TypeError);
  assert.throws(() => formatMediaType({ type: 'application', subtype: 'json', suffix: 'invalid+suffix' }), TypeError);
}

console.log('All media-typer contract assertions passed successfully.');