queue-microtask 1.2.3: Queue a callback function to execute asynchronously in the microtask queue

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: Queue a callback function to execute asynchronously in the microtask queue
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/queue-microtask@1.2.3
Demonstrate these symbols/APIs:
  - queueMicrotask
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:sha256:7e74bae1a1c8935f0325308426260fa0ae7917b5259c7f82d534b282b9986074","constraints":{"executionContext":"node"},"contract":["assert queueMicrotask is a function","assert callback passed to queueMicrotask runs asynchronously after synchronous execution completes","assert microtasks run in FIFO order before timer macrotasks"],"goal":"Queue a callback function to execute asynchronously in the microtask queue","kind":"HOW","packages":["pkg:npm/queue-microtask@1.2.3"],"schemaVersion":1,"symbols":["queueMicrotask"]},"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/queue-microtask@1.2.3"],"schemaVersion":1,"symbols":["queueMicrotask"],"verifierAdapter":"node-typescript@1"}

'use strict';

const queueMicrotask = require('queue-microtask');

function scheduleTask(callback) {
  queueMicrotask(callback);
}

module.exports = {
  scheduleTask,
  queueMicrotask
};

{
  "name": "sample-queue-microtask",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-queue-microtask",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "queue-microtask": "1.2.3"
      }
    },
    "node_modules/queue-microtask": {
      "version": "1.2.3",
      "resolved": "https://registry.npmjs.org/queue-microtask/-/queue-microtask-1.2.3.tgz",
      "integrity": "sha512-NuaNSa6flKT5JaSYQzJok04JzTL1CA6aGhv5rfLW3PgqA+M2ChpZQnAC8h8i4ZFkBS8X5RqkDBHA7r4hej3K9A==",
      "license": "MIT"
    }
  }
}

{
  "name": "sample-queue-microtask",
  "version": "1.0.0",
  "description": "Queue a callback function to execute asynchronously in the microtask queue",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.cjs"
  },
  "license": "MIT-0",
  "dependencies": {
    "queue-microtask": "1.2.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "Queue a callback function to execute asynchronously in the microtask queue",
  "kind": "HOW",
  "packages": [
    "pkg:npm/queue-microtask@1.2.3"
  ],
  "symbols": [
    "queueMicrotask"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

'use strict';

const assert = require('node:assert');
const queueMicrotask = require('queue-microtask');
const { scheduleTask } = require('../index.js');

// 1. Assert queueMicrotask is a function
assert.strictEqual(typeof queueMicrotask, 'function', 'queueMicrotask must be a function');
assert.strictEqual(typeof scheduleTask, 'function', 'scheduleTask must be a function');

let syncCompleted = false;
const executionOrder = [];

// 2. Schedule first microtask directly
queueMicrotask(() => {
  executionOrder.push('microtask-1');
  assert.strictEqual(syncCompleted, true, 'Microtask must execute after synchronous execution completes');
});

// 3. Schedule second microtask via wrapper function
scheduleTask(() => {
  executionOrder.push('microtask-2');
});

// 4. Schedule macrotask to verify microtasks execute before macrotasks and in FIFO order
setTimeout(() => {
  executionOrder.push('macrotask');
  assert.deepStrictEqual(
    executionOrder,
    ['microtask-1', 'microtask-2', 'macrotask'],
    'Microtasks must execute in FIFO order before timer macrotasks'
  );
  console.log('Contract verification succeeded.');
}, 50);

syncCompleted = true;