jest-worker 29.7.0: Worker

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 pkg:npm/jest-worker@29.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/jest-worker@29.7.0
Demonstrate these symbols/APIs:
  - Worker

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:sha256:643227f0dda4b2bf71719665c10a017de6806aa4f95a3321d98a78285bc87b26","contract":["Worker requires an absolute worker path upon instantiation","Worker executes exposed module methods in parallel worker threads and returns resolved results","Worker propagates exceptions thrown in worker methods as rejected promises","Worker supports custom sticky routing using computeWorkerKey","Worker provides stdout and stderr readable streams via getStdout and getStderr","Worker supports custom TaskQueue implementations including FifoQueue and PriorityQueue","Worker end gracefully terminates the worker farm and rejects subsequent method calls"],"goal":"verify pkg:npm/jest-worker@29.7.0","kind":"HOW","packages":["pkg:npm/jest-worker@29.7.0"],"schemaVersion":1,"symbols":["Worker"]},"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/jest-worker@29.7.0"],"schemaVersion":1,"subject":"pkg:npm/jest-worker@29.7.0","symbols":["Worker"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-jest-worker",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-jest-worker",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "jest-worker": "29.7.0"
      }
    },
    "node_modules/@jest/schemas": {
      "version": "29.6.3",
      "resolved": "https://registry.npmjs.org/@jest/schemas/-/schemas-29.6.3.tgz",
      "integrity": "sha512-mo5j5X+jIZmJQveBKeS/clAueipV7KgiX1vMgCxam1RNYiqE1w62n0/tJJnHtjW8ZHcQco5gY85jA3mi0L+nSA==",
      "license": "MIT",
      "dependencies": {
        "@sinclair/typebox": "^0.27.8"
      },
      "engines": {
        "node": "^14.15.0 || ^16.10.0 || >=18.0.0"
      }
    },
    "node_modules/@jest/types": {
      "version": "29.6.3",
      "resolved": "https://registry.npmjs.org/@jest/types/-/types-29.6.3.tgz",
      "integrity": "sha512-u3UPsIilWKOM3F9CXtrG8LEJmNxwoCQC/XVj4IKYXvvpx7QIi/Kg1LI5uDmDpKlac62NUtX7eLjRh+jVZcLOzw==",
      "license": "MIT",
      "dependencies": {
        "@jest/schemas": "^29.6.3",
        "@types/istanbul-lib-coverage": "^2.0.0",
        "@types/istanbul-reports": "^3.0.0",
        "@types/node": "*",
        "@types/yargs": "^17.0.8",
        "chalk": "^4.0.0"
      },
      "engines": {
        "node": "^14.15.0 || ^16.10.0 || >=18.0.0"
      }
    },
    "node_modules/@sinclair/typebox": {
      "version": "0.27.12",
      "resolved": "https://registry.npmjs.org/@sinclair/typebox/-/typebox-0.27.12.tgz",
      "integrity": "sha512-hhyNJ+nbR6ZR7pToHvllEFun9TL0sbL+tk/ON75lo+Xas054uez98qRbsuNt7MBCyZKK4+8Yli/OAGZhmfBZ/g==",
      "license": "MIT"
    },
    "node_modules/@types/istanbul-lib-coverage": {
      "version": "2.0.6",
      "resolved": "https://registry.npmjs.org/@types/istanbul-lib-coverage/-/istanbul-lib-coverage-2.0.6.tgz",
      "integrity": "sha512-2QF/t/auWm0lsy8XtKVPG19v3sSOQlJe/YHZgfjb/KBBHOGSV+J2q/S671rcq9uTBrLAXmZpqJiaQbMT+zNU1w==",
      "license": "MIT"
    },
    "node_modules/@types/istanbul-lib-report": {
      "version": "3.0.3",
      "resolved": "https://registry.npmjs.org/@types/istanbul-lib-report/-/istanbul-lib-report-3.0.3.tgz",
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      "license": "MIT",
      "dependencies": {
        "@types/istanbul-lib-coverage": "*"
      }
    },
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      "resolved": "https://registry.npmjs.org/@types/istanbul-reports/-/istanbul-reports-3.0.4.tgz",
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      "license": "MIT",
      "dependencies": {
        "@types/istanbul-lib-report": "*"
      }
    },
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      "version": "26.4.0",
      "resolved": "https://registry.npmjs.org/@types/node/-/node-26.4.0.tgz",
      "integrity": "sha512-faiGnoIrLH/V8cibOMEAZ8pMw6oXqSukl29ra4mN8GdaB2ZewzeaLj+INpV5N+Z1eKWzY+IzaIZH2EIR6YZRNQ==",
      "license": "MIT",
      "dependencies": {
        "undici-types": "~8.3.0"
      }
    },
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      "resolved": "https://registry.npmjs.org/@types/yargs/-/yargs-17.0.35.tgz",
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      "license": "MIT",
      "dependencies": {
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      }
    },
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      "resolved": "https://registry.npmjs.org/@types/yargs-parser/-/yargs-parser-21.0.3.tgz",
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      "license": "MIT"
    },
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      "license": "MIT",
      "dependencies": {
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      },
      "engines": {
        "node": ">=8"
      },
      "funding": {
        "url": "https://github.com/chalk/ansi-styles?sponsor=1"
      }
    },
    "node_modules/chalk": {
      "version": "4.1.2",
      "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.2.tgz",
      "integrity": "sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA==",
      "license": "MIT",
      "dependencies": {
        "ansi-styles": "^4.1.0",
        "supports-color": "^7.1.0"
      },
      "engines": {
        "node": ">=10"
      },
      "funding": {
        "url": "https://github.com/chalk/chalk?sponsor=1"
      }
    },
    "node_modules/chalk/node_modules/supports-color": {
      "version": "7.2.0",
      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-7.2.0.tgz",
      "integrity": "sha512-qpCAvRl9stuOHveKsn7HncJRvv501qIacKzQlO/+Lwxc9+0q2wLyv4Dfvt80/DPn2pqOBsJdDiogXGR9+OvwRw==",
      "license": "MIT",
      "dependencies": {
        "has-flag": "^4.0.0"
      },
      "engines": {
        "node": ">=8"
      }
    },
    "node_modules/ci-info": {
      "version": "3.9.0",
      "resolved": "https://registry.npmjs.org/ci-info/-/ci-info-3.9.0.tgz",
      "integrity": "sha512-NIxF55hv4nSqQswkAeiOi1r83xy8JldOFDTWiug55KBu9Jnblncd2U6ViHmYgHf01TPZS77NJBhBMKdWj9HQMQ==",
      "funding": [
        {
          "type": "github",
          "url": "https://github.com/sponsors/sibiraj-s"
        }
      ],
      "license": "MIT",
      "engines": {
        "node": ">=8"
      }
    },
    "node_modules/color-convert": {
      "version": "2.0.1",
      "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
      "integrity": "sha512-RRECPsj7iu/xb5oKYcsFHSppFNnsj/52OVTRKb4zP5onXwVF3zVmmToNcOfGC+CRDpfK/U584fMg38ZHCaElKQ==",
      "license": "MIT",
      "dependencies": {
        "color-name": "~1.1.4"
      },
      "engines": {
        "node": ">=7.0.0"
      }
    },
    "node_modules/color-name": {
      "version": "1.1.4",
      "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.4.tgz",
      "integrity": "sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA==",
      "license": "MIT"
    },
    "node_modules/graceful-fs": {
      "version": "4.2.11",
      "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.2.11.tgz",
      "integrity": "sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ==",
      "license": "ISC"
    },
    "node_modules/has-flag": {
      "version": "4.0.0",
      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-4.0.0.tgz",
      "integrity": "sha512-EykJT/Q1KjTWctppgIAgfSO0tKVuZUjhgMr17kqTumMl6Afv3EISleU7qZUzoXDFTAHTDC4NOoG/ZxU3EvlMPQ==",
      "license": "MIT",
      "engines": {
        "node": ">=8"
      }
    },
    "node_modules/jest-util": {
      "version": "29.7.0",
      "resolved": "https://registry.npmjs.org/jest-util/-/jest-util-29.7.0.tgz",
      "integrity": "sha512-z6EbKajIpqGKU56y5KBUgy1dt1ihhQJgWzUlZHArA/+X2ad7Cb5iF+AK1EWVL/Bo7Rz9uurpqw6SiBCefUbCGA==",
      "license": "MIT",
      "dependencies": {
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        "@types/node": "*",
        "chalk": "^4.0.0",
        "ci-info": "^3.2.0",
        "graceful-fs": "^4.2.9",
        "picomatch": "^2.2.3"
      },
      "engines": {
        "node": "^14.15.0 || ^16.10.0 || >=18.0.0"
      }
    },
    "node_modules/jest-worker": {
      "version": "29.7.0",
      "resolved": "https://registry.npmjs.org/jest-worker/-/jest-worker-29.7.0.tgz",
      "integrity": "sha512-eIz2msL/EzL9UFTFFx7jBTkeZfku0yUAyZZZmJ93H2TYEiroIx2PQjEXcwYtYl8zXCxb+PAmA2hLIt/6ZEkPHw==",
      "license": "MIT",
      "dependencies": {
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        "jest-util": "^29.7.0",
        "merge-stream": "^2.0.0",
        "supports-color": "^8.0.0"
      },
      "engines": {
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      "license": "MIT",
      "engines": {
        "node": ">=8.6"
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      "funding": {
        "url": "https://github.com/sponsors/jonschlinkert"
      }
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        "node": ">=10"
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      "funding": {
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      }
    },
    "node_modules/undici-types": {
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      "license": "MIT"
    }
  }
}

{
  "name": "sample-jest-worker",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "license": "MIT-0",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "jest-worker": "29.7.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/jest-worker@29.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/jest-worker@29.7.0"
  ],
  "symbols": [
    "Worker"
  ]
}

import path from 'node:path';
import { fileURLToPath } from 'node:url';
import { Worker, FifoQueue, PriorityQueue, messageParent } from 'jest-worker';

export { Worker, FifoQueue, PriorityQueue, messageParent };

const __dirname = path.dirname(fileURLToPath(import.meta.url));
export const DEFAULT_WORKER_PATH = path.join(__dirname, 'workerService.cjs');

/**
 * Creates a configured Worker farm for the worker service module.
 * @param {import('jest-worker').WorkerFarmOptions} [options]
 * @returns {Worker}
 */
export function createWorkerFarm(options = {}) {
  return new Worker(DEFAULT_WORKER_PATH, {
    numWorkers: 2,
    enableWorkerThreads: true,
    exposedMethods: [
      'computeSum',
      'computeProduct',
      'processTask',
      'throwingMethod',
      'echoMessage',
    ],
    ...options,
  });
}

'use strict';

/**
 * Worker service module executed inside worker threads or child processes.
 */

function computeSum(a, b) {
  return a + b;
}

function computeProduct(a, b) {
  return a * b;
}

function processTask(name, payload) {
  return {
    handled: true,
    task: name,
    resultLength: typeof payload === 'string' ? payload.length : 0,
  };
}

function throwingMethod(message) {
  throw new Error(message || 'Worker execution failed');
}

function echoMessage(data) {
  return data;
}

module.exports = {
  computeSum,
  computeProduct,
  processTask,
  throwingMethod,
  echoMessage,
};

import assert from 'node:assert';
import {
  Worker,
  FifoQueue,
  PriorityQueue,
  createWorkerFarm,
  DEFAULT_WORKER_PATH,
} from '../src/index.mjs';

// 1. Worker requires an absolute worker path upon instantiation
{
  assert.throws(
    () => {
      new Worker('relative/path/to/worker.js');
    },
    {
      name: 'Error',
      message: "'workerPath' must be absolute, got 'relative/path/to/worker.js'",
    }
  );
}

// 2. Worker executes exposed module methods in parallel worker threads and returns resolved results
{
  const farm = createWorkerFarm();
  const sum = await farm.computeSum(15, 27);
  assert.strictEqual(sum, 42);

  const product = await farm.computeProduct(6, 7);
  assert.strictEqual(product, 42);

  const task = await farm.processTask('build', 'sample-content');
  assert.strictEqual(task.handled, true);
  assert.strictEqual(task.task, 'build');
  assert.strictEqual(task.resultLength, 14);

  const echo = await farm.echoMessage({ ok: true, count: 5 });
  assert.deepStrictEqual(echo, { ok: true, count: 5 });

  await farm.end();
}

// 3. Worker propagates exceptions thrown in worker methods as rejected promises
{
  const farm = createWorkerFarm();
  await assert.rejects(
    async () => {
      await farm.throwingMethod('invalid operation in child thread');
    },
    {
      name: 'Error',
      message: 'invalid operation in child thread',
    }
  );
  await farm.end();
}

// 4. Worker supports custom sticky routing using computeWorkerKey
{
  let keyComputed = false;
  const farm = createWorkerFarm({
    computeWorkerKey: (method, ...args) => {
      keyComputed = true;
      return `sticky-${method}-${args[0]}`;
    },
  });

  const res1 = await farm.computeSum(10, 20);
  assert.strictEqual(res1, 30);
  assert.strictEqual(keyComputed, true);

  await farm.end();
}

// 5. Worker provides stdout and stderr readable streams via getStdout and getStderr
{
  const farm = createWorkerFarm();
  const stdout = farm.getStdout();
  const stderr = farm.getStderr();

  assert.strictEqual(typeof stdout.pipe, 'function');
  assert.strictEqual(typeof stdout.on, 'function');
  assert.strictEqual(typeof stderr.pipe, 'function');
  assert.strictEqual(typeof stderr.on, 'function');

  await farm.end();
}

// 6. Worker supports custom TaskQueue implementations including FifoQueue and PriorityQueue
{
  const fifoFarm = createWorkerFarm({
    taskQueue: new FifoQueue(),
  });
  const fifoRes = await fifoFarm.computeSum(5, 5);
  assert.strictEqual(fifoRes, 10);
  await fifoFarm.end();

  const pqFarm = createWorkerFarm({
    taskQueue: new PriorityQueue((method, a) => (typeof a === 'number' ? a : 0)),
  });
  const pqRes = await pqFarm.computeProduct(3, 4);
  assert.strictEqual(pqRes, 12);
  await pqFarm.end();
}

// 7. Worker end gracefully terminates the worker farm and rejects subsequent method calls
{
  const farm = createWorkerFarm();
  const preCheck = await farm.computeSum(1, 1);
  assert.strictEqual(preCheck, 2);

  const endResult = await farm.end();
  assert.strictEqual(typeof endResult, 'object');

  await assert.rejects(
    async () => {
      await farm.computeSum(1, 2);
    },
    {
      name: 'Error',
      message: 'Farm is ended, no more calls can be done to it',
    }
  );
}

console.log('All jest-worker contract assertions passed.');