depd 2.0.0

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/depd@2.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/depd@2.0.0
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:bb5b3a6cb602d99bacc0bd194029235e0d6197b7b9ed4c12ce3cb33d50bf7eac","constraints":{"executionContext":"node"},"contract":["depd(namespace) returns a deprecation logging function for the specified namespace","depd() throws TypeError when namespace argument is omitted or falsy","deprecate(message) emits a deprecation event on process containing namespace and message details","deprecateFunction(namespace, fn, message) wraps a function to emit deprecation warning while preserving arguments and return value","deprecateProperty(namespace, obj, prop, message) wraps an object property to emit deprecation warning on getter access and setter modification"],"goal":"verify pkg:npm/depd@2.0.0","kind":"HOW","packages":["pkg:npm/depd@2.0.0"],"schemaVersion":1},"contractCommand":["node","test/contract.cjs"],"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/depd@2.0.0"],"schemaVersion":1,"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-depd",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-depd",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "depd": "2.0.0"
      }
    },
    "node_modules/depd": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/depd/-/depd-2.0.0.tgz",
      "integrity": "sha512-g7nH6P6dyDioJogAAGprGpCtVImJhpPk/roCzdb3fIh61/s/nPsfR6onyMwkCAR/OlC3yBC0lESvUoQEAssIrw==",
      "license": "MIT",
      "engines": {
        "node": ">= 0.8"
      }
    }
  }
}

{
  "name": "sample-depd",
  "version": "1.0.0",
  "private": true,
  "description": "Clean-room verification for depd",
  "main": "src/index.js",
  "license": "MIT-0",
  "dependencies": {
    "depd": "2.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/depd@2.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/depd@2.0.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

const depd = require('depd');

/**
 * Create a deprecation function for the given namespace.
 * @param {string} namespace - Namespace identifying the deprecated module
 * @returns {Function} Deprecate function
 */
function createDeprecator(namespace) {
  return depd(namespace);
}

/**
 * Wrap a function to log a deprecation warning on first invocation.
 * @param {string} namespace - Namespace identifying the deprecated module
 * @param {Function} fn - Function to deprecate
 * @param {string} [message] - Deprecation message
 * @returns {Function} Wrapped deprecated function
 */
function deprecateFunction(namespace, fn, message) {
  const deprecate = depd(namespace);
  return deprecate.function(fn, message);
}

/**
 * Wrap an object property to log a deprecation warning on access or mutation.
 * @param {string} namespace - Namespace identifying the deprecated module
 * @param {object} obj - Object containing the property
 * @param {string} prop - Name of the property to deprecate
 * @param {string} [message] - Deprecation message
 */
function deprecateProperty(namespace, obj, prop, message) {
  const deprecate = depd(namespace);
  deprecate.property(obj, prop, message);
}

module.exports = {
  depd,
  createDeprecator,
  deprecateFunction,
  deprecateProperty
};

const assert = require('node:assert');
const {
  depd,
  createDeprecator,
  deprecateFunction,
  deprecateProperty
} = require('../src/index.js');

// 1. Export verification
assert.strictEqual(typeof depd, 'function', 'depd must be a function');
assert.strictEqual(typeof createDeprecator, 'function', 'createDeprecator must be a function');
assert.strictEqual(typeof deprecateFunction, 'function', 'deprecateFunction must be a function');
assert.strictEqual(typeof deprecateProperty, 'function', 'deprecateProperty must be a function');

// 2. depd(namespace) returns deprecator with function and property helpers
const deprecate = createDeprecator('sample-pkg');
assert.strictEqual(typeof deprecate, 'function', 'deprecator must be a function');
assert.strictEqual(typeof deprecate.function, 'function', 'deprecate.function must be a function');
assert.strictEqual(typeof deprecate.property, 'function', 'deprecate.property must be a function');

// 3. depd throws TypeError when namespace is missing or empty
assert.throws(() => depd(), TypeError, 'depd() without arguments must throw TypeError');
assert.throws(() => depd(''), TypeError, 'depd("") with empty namespace must throw TypeError');
assert.throws(() => depd(null), TypeError, 'depd(null) must throw TypeError');

// Set up deprecation listener on process
const events = [];
const onDeprecation = (err) => {
  events.push(err);
};
process.on('deprecation', onDeprecation);

try {
  // 4. deprecate(message) emits deprecation event on process
  deprecate('legacyFunction is deprecated');
  assert.strictEqual(events.length, 1);
  assert.strictEqual(events[0].name, 'DeprecationError');
  assert.strictEqual(events[0].namespace, 'sample-pkg');
  assert.ok(events[0].message.includes('legacyFunction is deprecated'));

  // 5. deprecateFunction wraps function, forwards arguments, and preserves return value
  function calculateTotal(price, taxRate) {
    return price + price * taxRate;
  }
  const deprecatedCalculate = deprecateFunction('calc-pkg', calculateTotal, 'calculateTotal is deprecated');
  const total = deprecatedCalculate(100, 0.1);
  assert.strictEqual(total, 110);
  assert.strictEqual(events.length, 2);
  assert.strictEqual(events[1].namespace, 'calc-pkg');
  assert.ok(events[1].message.includes('calculateTotal is deprecated'));

  // 6. deprecateProperty wraps object property for read and write access
  const config = { maxRetries: 3 };
  deprecateProperty('config-pkg', config, 'maxRetries', 'maxRetries is deprecated, use retryLimit');
  assert.strictEqual(config.maxRetries, 3);
  assert.strictEqual(events.length, 3);
  assert.strictEqual(events[2].namespace, 'config-pkg');
  assert.ok(events[2].message.includes('maxRetries is deprecated'));

  config.maxRetries = 5;
  assert.strictEqual(config.maxRetries, 5);
} finally {
  process.removeListener('deprecation', onDeprecation);
}

console.log('Contract tests passed successfully.');