lowercase-keys 2.0.0: lowercase the keys of an object

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: lowercase the keys of an object
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/lowercase-keys@2.0.0
Demonstrate these symbols/APIs:
  - lowercaseKeys

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:e47ec1de9ad1c63e46504c972a9debe1e0288e6da968791574dcdccbf999868e","contract":["lowercaseKeys transforms all own enumerable property keys of an object to lowercase","lowercaseKeys preserves the associated values of transformed keys","lowercaseKeys returns a shallow copy and does not mutate the source object","lowercaseKeys overwrites earlier properties if multiple keys collide when lowercased","lowercaseKeys returns an empty object when passed an empty object"],"goal":"lowercase the keys of an object","kind":"HOW","packages":["pkg:npm/lowercase-keys@2.0.0"],"schemaVersion":1,"symbols":["lowercaseKeys"]},"contractCommand":["node","test/contract.js"],"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/lowercase-keys@2.0.0"],"schemaVersion":1,"subject":"pkg:npm/lowercase-keys@2.0.0","symbols":["lowercaseKeys"],"verifierAdapter":"node-typescript@1"}

'use strict';

const lowercaseKeys = require('lowercase-keys');

/**
 * Normalizes all keys of an object to lowercase.
 *
 * @param {Record<string, any>} object
 * @returns {Record<string, any>}
 */
function normalizeObjectKeys(object) {
  return lowercaseKeys(object);
}

module.exports = {
  normalizeObjectKeys,
  lowercaseKeys
};

{
  "name": "sample-lowercase-keys",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-lowercase-keys",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "lowercase-keys": "2.0.0"
      }
    },
    "node_modules/lowercase-keys": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/lowercase-keys/-/lowercase-keys-2.0.0.tgz",
      "integrity": "sha512-tqNXrS78oMOE73NMxK4EMLQsQowWf8jKooH9g7xPavRT706R6bkQJ6DY2Te7QukaZsulxa30wQ7bk0pm4XiHmA==",
      "license": "MIT",
      "engines": {
        "node": ">=8"
      }
    }
  }
}

{
  "name": "sample-lowercase-keys",
  "version": "1.0.0",
  "private": true,
  "description": "lowercase the keys of an object",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "lowercase-keys": "2.0.0"
  },
  "license": "MIT-0"
}

{
  "schemaVersion": 1,
  "goal": "lowercase the keys of an object",
  "kind": "HOW",
  "packages": [
    "pkg:npm/lowercase-keys@2.0.0"
  ],
  "symbols": [
    "lowercaseKeys"
  ]
}

'use strict';

const assert = require('assert');
const lowercaseKeys = require('lowercase-keys');
const { normalizeObjectKeys } = require('../index.js');

// 1. lowercaseKeys transforms all own enumerable property keys of an object to lowercase
const input = { FOO: 'bar', Baz: 42, 'QUX-KEY': true };
const output = lowercaseKeys(input);
assert.deepStrictEqual(output, { foo: 'bar', baz: 42, 'qux-key': true });

// 2. lowercaseKeys preserves the associated values of transformed keys
const complexInput = {
  A: [1, 2, 3],
  B: { nested: 'value' },
  C: null,
  D: undefined
};
const complexOutput = lowercaseKeys(complexInput);
assert.strictEqual(complexOutput.a, complexInput.A);
assert.strictEqual(complexOutput.b, complexInput.B);
assert.strictEqual(complexOutput.c, null);
assert.strictEqual(complexOutput.d, undefined);

// 3. lowercaseKeys returns a shallow copy and does not mutate the source object
const original = { KEY: 'val' };
const transformed = lowercaseKeys(original);
assert.notStrictEqual(transformed, original);
assert.deepStrictEqual(original, { KEY: 'val' });

// 4. lowercaseKeys overwrites earlier properties if multiple keys collide when lowercased
const collision = { aA: 1, AA: 2, aa: 3 };
assert.deepStrictEqual(lowercaseKeys(collision), { aa: 3 });

// 5. lowercaseKeys returns an empty object when passed an empty object
assert.deepStrictEqual(lowercaseKeys({}), {});

// 6. normalizeObjectKeys wrapper works identically
const helperOutput = normalizeObjectKeys({ FIRST_NAME: 'Alice', LAST_NAME: 'Smith' });
assert.deepStrictEqual(helperOutput, { first_name: 'Alice', last_name: 'Smith' });

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