std-env 4.2.0: env

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 std-env.env in pkg:npm/std-env@4.2.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/std-env@4.2.0
Demonstrate these symbols/APIs:
  - std-env.env
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:e689a30781d277e121b5b861469f6e03bbe07a94382b849b5f196ab194ce8c1a","constraints":{"executionContext":"node"},"contract":["env is an object proxy for cross-runtime environment variables","env proxy reads existing environment variables matching process.env","'in' operator checks presence of variable in env proxy","writing property via env proxy sets the variable","deleting property via env proxy removes the variable","accessing non-existent key on env returns undefined","Reflect.ownKeys on env returns array containing environment keys"],"goal":"verify std-env.env in pkg:npm/std-env@4.2.0","kind":"HOW","packages":["pkg:npm/std-env@4.2.0"],"schemaVersion":1,"symbols":["std-env.env"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/std-env@4.2.0"],"schemaVersion":1,"subject":"pkg:npm/std-env@4.2.0","symbols":["std-env.env"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-std-env",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-std-env",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "std-env": "4.2.0"
      }
    },
    "node_modules/std-env": {
      "version": "4.2.0",
      "resolved": "https://registry.npmjs.org/std-env/-/std-env-4.2.0.tgz",
      "integrity": "sha512-oCUKSupKTHX53EyjDtuZQ64pjLJ6yYCtpmEw0goYxtjG9KpbRe8KAsl2tBUGU9DyMcJ0RwJ8GqJAFzMXcXW1Rw==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-std-env",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "std-env": "4.2.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify std-env.env in pkg:npm/std-env@4.2.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/std-env@4.2.0"
  ],
  "symbols": [
    "std-env.env"
  ],
  "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 { env } from 'std-env';

// 1. env is an object proxy for cross-runtime environment variables
assert.strictEqual(typeof env, 'object', 'env is an object proxy');

// 2. env proxy reads existing environment variables matching process.env
assert.strictEqual(typeof env.PATH, 'string', 'env.PATH is a string');
assert.strictEqual(env.PATH, process.env.PATH, 'env proxy matches process.env');

// 3. 'in' operator checks presence of variable in env proxy
assert.strictEqual('PATH' in env, true, 'in operator detects PATH in env');

// 4. writing property via env proxy sets the variable
env.CSX_PROXY_FIELD = 'active';
assert.strictEqual(env.CSX_PROXY_FIELD, 'active', 'reading back value written via env proxy');
assert.strictEqual('CSX_PROXY_FIELD' in env, true, 'in operator reflects newly added property');

// 5. deleting property via env proxy removes the variable
delete env.CSX_PROXY_FIELD;
assert.strictEqual('CSX_PROXY_FIELD' in env, false, 'in operator reflects deleted property');
assert.strictEqual(env.CSX_PROXY_FIELD, undefined, 'deleted property returns undefined');

// 6. accessing non-existent key on env returns undefined
assert.strictEqual(env.NON_EXISTENT_SAMPLE_KEY_XYZ, undefined, 'non-existent key returns undefined');

// 7. Reflect.ownKeys on env returns array containing environment keys
const ownKeys = Reflect.ownKeys(env);
assert.strictEqual(Array.isArray(ownKeys), true, 'Reflect.ownKeys returns array');
assert.strictEqual(ownKeys.includes('PATH'), true, 'Reflect.ownKeys includes PATH');