std-env 3.10.0: isBun

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.isBun in pkg:npm/std-env@3.10.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/std-env@3.10.0
Demonstrate these symbols/APIs:
  - std-env.isBun

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:sha256:3c96cb47f6be63a4dd36e8d6f76e46104261e410a9ac6d2a019e8e052dca2687","contract":["isBun is exported as a boolean flag from std-env","isBun evaluates to false in standard Node.js environment","isBun is consistent with runtime property evaluating to 'node' rather than 'bun' in Node.js","isBun is mutually exclusive with isNode in standard Node.js execution","isBun evaluates to true when globalThis.Bun is defined","isBun evaluates to true when process.versions.bun is defined","runtime evaluates to 'bun' when isBun is active"],"goal":"verify std-env.isBun in pkg:npm/std-env@3.10.0","kind":"HOW","packages":["pkg:npm/std-env@3.10.0"],"schemaVersion":1,"symbols":["std-env.isBun"]},"contractCommand":["node","test/contract.mjs"],"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/std-env@3.10.0"],"schemaVersion":1,"subject":"pkg:npm/std-env@3.10.0","symbols":["std-env.isBun"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-std-env-isbun",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-std-env-isbun",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "std-env": "3.10.0"
      }
    },
    "node_modules/std-env": {
      "version": "3.10.0",
      "resolved": "https://registry.npmjs.org/std-env/-/std-env-3.10.0.tgz",
      "integrity": "sha512-5GS12FdOZNliM5mAOxFRg7Ir0pWz8MdpYm6AY6VPkGpbA7ZzmbzNcBJQ0GPvvyWgcY7QAhCgf9Uy89I03faLkg==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-std-env-isbun",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "std-env": "3.10.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify std-env.isBun in pkg:npm/std-env@3.10.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/std-env@3.10.0"
  ],
  "symbols": [
    "std-env.isBun"
  ]
}

import assert from 'node:assert/strict';
import { isBun, runtime, isNode, runtimeInfo } from 'std-env';

// 1. isBun is exported as a boolean flag from std-env
assert.strictEqual(typeof isBun, 'boolean', 'isBun must be a boolean');

// 2. isBun evaluates to false in standard Node.js environment
assert.strictEqual(isBun, false, 'isBun evaluates to false under Node.js');

// 3. isBun is consistent with runtime property evaluating to 'node' rather than 'bun' in Node.js
assert.strictEqual(runtime, 'node', 'runtime evaluates to "node" in Node.js');
assert.notStrictEqual(runtime, 'bun', 'runtime is not "bun" in Node.js');
assert.deepStrictEqual(runtimeInfo, { name: 'node' }, 'runtimeInfo matches node environment');

// 4. isBun is mutually exclusive with isNode in standard Node.js execution
assert.strictEqual(isNode, true, 'isNode evaluates to true in Node.js');
assert.notStrictEqual(isBun, isNode, 'isBun and isNode are mutually exclusive in Node.js');

const stdEnvUrl = import.meta.resolve('std-env');

// 5. isBun evaluates to true when globalThis.Bun is defined
{
  globalThis.Bun = { version: '1.1.0' };
  try {
    const mod = await import(`${stdEnvUrl}?case=global-bun`);
    assert.strictEqual(mod.isBun, true, 'isBun is true when globalThis.Bun is defined');
    assert.strictEqual(mod.runtime, 'bun', 'runtime is "bun" when globalThis.Bun is defined');
  } finally {
    delete globalThis.Bun;
  }
}

// 6. isBun evaluates to true when process.versions.bun is defined
{
  process.versions.bun = '1.1.0';
  try {
    const mod = await import(`${stdEnvUrl}?case=process-bun`);
    assert.strictEqual(mod.isBun, true, 'isBun is true when process.versions.bun is defined');
    assert.strictEqual(mod.runtime, 'bun', 'runtime is "bun" when process.versions.bun is defined');
  } finally {
    delete process.versions.bun;
  }
}

// 7. runtime evaluates to 'bun' when isBun is active
{
  globalThis.Bun = {};
  try {
    const mod = await import(`${stdEnvUrl}?case=bun-runtime-check`);
    assert.strictEqual(mod.isBun, true, 'isBun is active');
    assert.strictEqual(mod.runtime, 'bun', 'runtime is bun when isBun is active');
    assert.deepStrictEqual(mod.runtimeInfo, { name: 'bun' }, 'runtimeInfo name is bun');
  } finally {
    delete globalThis.Bun;
  }
}

console.log('Contract passed');