why-is-node-running 2.3.0: identify active asynchronous handles keeping node process alive

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: identify active asynchronous handles keeping node process alive
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/why-is-node-running@2.3.0
Demonstrate these symbols/APIs:
  - whyIsNodeRunning

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:sha256:4b2e5379d3ec69bae749efb1b504d265069173ec88457f9a0e3a28eaed2fee4b","contract":["whyIsNodeRunning invokes custom logger error method with formatted handle count and active handle types","inspectActiveHandles wrapper delegates correctly to whyIsNodeRunning","whyIsNodeRunning ignores unreferenced handles that do not keep process running","whyIsNodeRunning falls back to console logger when no custom logger is provided"],"goal":"identify active asynchronous handles keeping node process alive","kind":"HOW","packages":["pkg:npm/why-is-node-running@2.3.0"],"schemaVersion":1,"symbols":["whyIsNodeRunning"]},"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/why-is-node-running@2.3.0"],"schemaVersion":1,"subject":"pkg:npm/why-is-node-running@2.3.0","symbols":["whyIsNodeRunning"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-why-is-node-running",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-why-is-node-running",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "why-is-node-running": "2.3.0"
      }
    },
    "node_modules/siginfo": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/siginfo/-/siginfo-2.0.0.tgz",
      "integrity": "sha512-ybx0WO1/8bSBLEWXZvEd7gMW3Sn3JFlW3TvX1nREbDLRNQNaeNN8WK0meBwPdAaOI7TtRRRJn/Es1zhrrCHu7g==",
      "license": "ISC"
    },
    "node_modules/stackback": {
      "version": "0.0.2",
      "resolved": "https://registry.npmjs.org/stackback/-/stackback-0.0.2.tgz",
      "integrity": "sha512-1XMJE5fQo1jGH6Y/7ebnwPOBEkIEnT4QF32d5R1+VXdXveM0IBMJt8zfaxX1P3QhVwrYe+576+jkANtSS2mBbw==",
      "license": "MIT"
    },
    "node_modules/why-is-node-running": {
      "version": "2.3.0",
      "resolved": "https://registry.npmjs.org/why-is-node-running/-/why-is-node-running-2.3.0.tgz",
      "integrity": "sha512-hUrmaWBdVDcxvYqnyh09zunKzROWjbZTiNy8dBEjkS7ehEDQibXJ7XvlmtbwuTclUiIyN+CyXQD4Vmko8fNm8w==",
      "license": "MIT",
      "dependencies": {
        "siginfo": "^2.0.0",
        "stackback": "0.0.2"
      },
      "bin": {
        "why-is-node-running": "cli.js"
      },
      "engines": {
        "node": ">=8"
      }
    }
  }
}

{
  "name": "sample-why-is-node-running",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "dependencies": {
    "why-is-node-running": "2.3.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "identify active asynchronous handles keeping node process alive",
  "kind": "HOW",
  "packages": [
    "pkg:npm/why-is-node-running@2.3.0"
  ],
  "symbols": [
    "whyIsNodeRunning"
  ]
}

import whyIsNodeRunning from "why-is-node-running";

/**
 * Inspects active asynchronous handles keeping the Node.js process alive.
 * @param {object} [logger] - Custom logger object with an error method.
 */
export function inspectActiveHandles(logger) {
  whyIsNodeRunning(logger);
}

export { whyIsNodeRunning };
export default whyIsNodeRunning;

import assert from "node:assert/strict";
import net from "node:net";
import util from "node:util";
import { whyIsNodeRunning, inspectActiveHandles } from "../src/index.mjs";

async function runContract() {
  // 1. whyIsNodeRunning invokes custom logger error method with formatted handle count and active handle types
  const logs = [];
  const customLogger = {
    error: (...args) => {
      logs.push(util.format(...args));
    },
  };

  const server = net.createServer();
  await new Promise((resolve) => server.listen(0, "127.0.0.1", resolve));

  whyIsNodeRunning(customLogger);

  const countLog = logs.find((l) =>
    l.includes("handle(s) keeping the process running")
  );
  assert.ok(countLog, "Logger must record handle count message");
  assert.match(countLog, /There are \d+ handle\(s\) keeping the process running/);

  const serverWrapLog = logs.find((l) => l.includes("# TCPSERVERWRAP"));
  assert.ok(
    serverWrapLog,
    "Logger must identify active TCPSERVERWRAP handle type"
  );

  await new Promise((resolve) => server.close(resolve));

  // 2. inspectActiveHandles wrapper delegates correctly to whyIsNodeRunning
  const wrapperLogs = [];
  const wrapperLogger = {
    error: (...args) => {
      wrapperLogs.push(util.format(...args));
    },
  };
  inspectActiveHandles(wrapperLogger);
  const wrapperCountLog = wrapperLogs.find((l) =>
    l.includes("handle(s) keeping the process running")
  );
  assert.ok(
    wrapperCountLog,
    "inspectActiveHandles must invoke underlying whyIsNodeRunning logic"
  );

  // 3. whyIsNodeRunning ignores unreferenced handles that do not keep process running
  const unrefLogs = [];
  const unrefLogger = {
    error: (...args) => {
      unrefLogs.push(util.format(...args));
    },
  };
  const unrefTimer = setTimeout(() => {}, 60000);
  unrefTimer.unref();

  whyIsNodeRunning(unrefLogger);

  const timerEntry = unrefLogs.find((l) => l.includes("# Timeout"));
  assert.equal(
    timerEntry,
    undefined,
    "Unreferenced timer handles must not be logged as active keepalive handles"
  );
  clearTimeout(unrefTimer);

  // 4. whyIsNodeRunning falls back to console logger when no custom logger is provided
  let consoleErrorCalled = false;
  const originalConsoleError = console.error;
  console.error = (...args) => {
    consoleErrorCalled = true;
    originalConsoleError(...args);
  };
  try {
    whyIsNodeRunning();
    assert.equal(
      consoleErrorCalled,
      true,
      "console.error must be called when logger argument is omitted"
    );
  } finally {
    console.error = originalConsoleError;
  }

  console.log("All contract assertions passed successfully.");
}

runContract().catch((err) => {
  console.error("Contract test failed:", err);
  process.exit(1);
});