CodeSampleX

Ejemplo

@jest/fake-timers 29.7.0: ModernFakeTimers, LegacyFakeTimers

Muestra verificada para npm @jest/fake-timers 29.7.0: ModernFakeTimers, LegacyFakeTimers. El contrato se ejecutó en node 22 · linux alpine/x64 · docker y…

sha256:f3a9f946a4a29a2eac730a1e515046fa2eb34a226bc6d89d8cd2386cfc306339

Esta red ofrece una sola cosa: una muestra que compila. La ejecutó en un sandbox y guardó el recibo firmado. No califica ni garantiza nada: si el mismo código compila donde estás no es algo que haya medido. Cuántas claves de firma distintas presentaron un recibo de contrato aprobado. Una es solo el autor; más de una significa que alguien más también lo compiló. Una clave se genera sola y no tiene identidad registrada detrás, así que cuenta claves, no personas. MIT-0

Evidencia de ejecución

El entorno declarado y las ejecuciones firmadas se muestran por separado, para que veas exactamente qué ejecutó esta muestra y dónde.

Base de evidencia
Contrato firmado aprobado
Recibos de verificación
1
Claves de firma que lo compilaron
1
Entorno declarado node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript npm 10

Entornos de las ejecuciones de verificación

Entorno Contrato Etapas Ejecución
node 22 · linux alpine/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22-alpine@sha256:c610fcdfb1d5…		 2026-08-28

Caso

HOW
Objetivo
verify pkg:npm/%40jest/fake-timers@29.7.0
Paquetes
Símbolos
  • ModernFakeTimers
  • LegacyFakeTimers
Entorno
node 22.23.2
Creado
2026-08-28T03:09:44Z

Contrato

  1. ModernFakeTimers installs fake timer mocks with useFakeTimers and restores original implementations on useRealTimers
  2. advanceTimersByTime advances virtual clock and executes scheduled timers synchronously
  3. advanceTimersByTimeAsync advances virtual clock asynchronously and resolves promises
  4. advanceTimersToNextTimer and advanceTimersToNextTimerAsync progress virtual time to the next pending timer
  5. runAllTimers and runAllTimersAsync execute all queued and recursively scheduled timers
  6. runOnlyPendingTimers and runOnlyPendingTimersAsync execute currently queued timers without running newly scheduled nested timers
  7. clearAllTimers and getTimerCount track and cancel active scheduled timers
  8. setSystemTime, getRealSystemTime, now, and reset manage and simulate system timestamps
  9. LegacyFakeTimers installs timer mocks, manages clock advancement, and executes runWithRealTimers callback
  10. withFakeTimers and withFakeTimersAsync helpers safely execute scoped synchronous and asynchronous callbacks

Archivos

  • PROMPT.md
  • csx.json
  • index.js
  • package-lock.json
  • package.json
  • spec.json
  • test/contract.js

Descargar el artefacto de código fuente (tar.gz)

Código fuente

PROMPT.md
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/%40jest/fake-timers@29.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jest/fake-timers@29.7.0
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.
csx.json
{"case":{"caseId":"case:sha256:10661d99357f799bcaf336b869eb88bb840578a2515bdbcb98d20acdf2b3f28f","constraints":{"executionContext":"node"},"contract":["ModernFakeTimers installs fake timer mocks with useFakeTimers and restores original implementations on useRealTimers","advanceTimersByTime advances virtual clock and executes scheduled timers synchronously","advanceTimersByTimeAsync advances virtual clock asynchronously and resolves promises","advanceTimersToNextTimer and advanceTimersToNextTimerAsync progress virtual time to the next pending timer","runAllTimers and runAllTimersAsync execute all queued and recursively scheduled timers","runOnlyPendingTimers and runOnlyPendingTimersAsync execute currently queued timers without running newly scheduled nested timers","clearAllTimers and getTimerCount track and cancel active scheduled timers","setSystemTime, getRealSystemTime, now, and reset manage and simulate system timestamps","LegacyFakeTimers installs timer mocks, manages clock advancement, and executes runWithRealTimers callback","withFakeTimers and withFakeTimersAsync helpers safely execute scoped synchronous and asynchronous callbacks"],"goal":"verify pkg:npm/%40jest/fake-timers@29.7.0","kind":"HOW","packages":["pkg:npm/%40jest/fake-timers@29.7.0"],"schemaVersion":1,"symbols":["ModernFakeTimers","LegacyFakeTimers"]},"contractCommand":["node","test/contract.js"],"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/%40jest/fake-timers@29.7.0"],"schemaVersion":1,"subject":"pkg:npm/%40jest/fake-timers@29.7.0","symbols":["ModernFakeTimers","LegacyFakeTimers"],"verifierAdapter":"node-typescript@1"}
index.js
'use strict';

const { ModernFakeTimers, LegacyFakeTimers } = require('@jest/fake-timers');

/**
 * Creates and configures a ModernFakeTimers instance.
 * @param {Object} [options]
 * @param {Object} [options.global] - Target global object (defaults to globalThis)
 * @param {Object} [options.config] - Jest project configuration
 * @returns {ModernFakeTimers}
 */
function createModernFakeTimers(options = {}) {
  const {
    global = globalThis,
    config = { rootDir: process.cwd() }
  } = options;
  return new ModernFakeTimers({ global, config });
}

/**
 * Creates and configures a LegacyFakeTimers instance with a mock environment.
 * @param {Object} [options]
 * @param {Object} [options.global] - Custom global object to mock
 * @param {Object} [options.config] - Stack trace configuration
 * @param {Object} [options.timerConfig] - Timer ref/id mappings
 * @param {Object} [options.moduleMocker] - Module mocker instance
 * @param {number} [options.maxLoops] - Maximum execution loops
 * @returns {{ timers: LegacyFakeTimers, global: Object }}
 */
function createLegacyFakeTimers(options = {}) {
  const targetGlobal = {
    clearImmediate: globalThis.clearImmediate,
    clearInterval: globalThis.clearInterval,
    clearTimeout: globalThis.clearTimeout,
    setImmediate: globalThis.setImmediate,
    setInterval: globalThis.setInterval,
    setTimeout: globalThis.setTimeout,
    process: { nextTick: process.nextTick },
    console: console,
    ...(options.global || {})
  };

  const moduleMocker = options.moduleMocker || {
    fn: (impl) => {
      const mockFn = (...args) => (impl ? impl(...args) : undefined);
      return mockFn;
    }
  };

  const timerConfig = options.timerConfig || {
    idToRef: (id) => id,
    refToId: (ref) => ref
  };

  const config = options.config || { rootDir: process.cwd() };

  const timers = new LegacyFakeTimers({
    global: targetGlobal,
    moduleMocker,
    timerConfig,
    config,
    maxLoops: options.maxLoops
  });

  return { timers, global: targetGlobal };
}

/**
 * Executes a callback within a scoped ModernFakeTimers context and ensures clean restoration.
 * @param {Function} callback - Function receiving fake timers instance
 * @param {Object} [config] - Fake timers configuration options
 * @returns {*} Result of the callback
 */
function withFakeTimers(callback, config = {}) {
  const fakeTimers = createModernFakeTimers();
  fakeTimers.useFakeTimers(config);
  try {
    return callback(fakeTimers);
  } finally {
    fakeTimers.useRealTimers();
    fakeTimers.dispose();
  }
}

/**
 * Executes an async callback within a scoped ModernFakeTimers context and ensures clean restoration.
 * @param {Function} callback - Async function receiving fake timers instance
 * @param {Object} [config] - Fake timers configuration options
 * @returns {Promise<*>} Result of the async callback
 */
async function withFakeTimersAsync(callback, config = {}) {
  const fakeTimers = createModernFakeTimers();
  fakeTimers.useFakeTimers(config);
  try {
    return await callback(fakeTimers);
  } finally {
    fakeTimers.useRealTimers();
    fakeTimers.dispose();
  }
}

module.exports = {
  ModernFakeTimers,
  LegacyFakeTimers,
  createModernFakeTimers,
  createLegacyFakeTimers,
  withFakeTimers,
  withFakeTimersAsync
};
package-lock.json
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package.json
{
  "name": "sample-jest-fake-timers",
  "version": "1.0.0",
  "private": true,
  "description": "verify pkg:npm/%40jest/fake-timers@29.7.0",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "@jest/fake-timers": "29.7.0"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/%40jest/fake-timers@29.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jest/fake-timers@29.7.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}
test/contract.js
'use strict';

const assert = require('assert');
const {
  ModernFakeTimers,
  LegacyFakeTimers,
  createModernFakeTimers,
  createLegacyFakeTimers,
  withFakeTimers,
  withFakeTimersAsync
} = require('../index.js');

async function runContractTests() {
  // 1. ModernFakeTimers installs fake timer mocks with useFakeTimers and restores original implementations on useRealTimers
  {
    const originalSetTimeout = globalThis.setTimeout;
    const originalClearTimeout = globalThis.clearTimeout;
    const originalDate = globalThis.Date;

    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    assert.notStrictEqual(globalThis.setTimeout, originalSetTimeout);
    assert.notStrictEqual(globalThis.clearTimeout, originalClearTimeout);
    assert.notStrictEqual(globalThis.Date, originalDate);

    fake.useRealTimers();

    assert.strictEqual(globalThis.setTimeout, originalSetTimeout);
    assert.strictEqual(globalThis.clearTimeout, originalClearTimeout);
    assert.strictEqual(globalThis.Date, originalDate);
    fake.dispose();
  }

  // 2. advanceTimersByTime advances virtual clock and executes scheduled timers synchronously
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    const log = [];
    globalThis.setTimeout(() => log.push('first'), 100);
    globalThis.setTimeout(() => log.push('second'), 300);
    globalThis.setInterval(() => log.push('interval'), 150);

    fake.advanceTimersByTime(100);
    assert.deepStrictEqual(log, ['first']);

    fake.advanceTimersByTime(100);
    assert.deepStrictEqual(log, ['first', 'interval']);

    fake.advanceTimersByTime(100);
    assert.deepStrictEqual(log, ['first', 'interval', 'second', 'interval']);

    fake.useRealTimers();
    fake.dispose();
  }

  // 3. advanceTimersByTimeAsync advances virtual clock asynchronously and resolves promises
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    let resolved = false;
    const promise = new Promise((resolve) => {
      globalThis.setTimeout(() => {
        resolved = true;
        resolve('done');
      }, 500);
    });

    assert.strictEqual(resolved, false);
    await fake.advanceTimersByTimeAsync(500);
    const result = await promise;
    assert.strictEqual(resolved, true);
    assert.strictEqual(result, 'done');

    fake.useRealTimers();
    fake.dispose();
  }

  // 4. advanceTimersToNextTimer and advanceTimersToNextTimerAsync progress virtual time to the next pending timer
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    const events = [];
    globalThis.setTimeout(() => events.push('a'), 100);
    globalThis.setTimeout(() => events.push('b'), 250);
    globalThis.setTimeout(() => events.push('c'), 400);

    assert.strictEqual(fake.getTimerCount(), 3);
    fake.advanceTimersToNextTimer();
    assert.deepStrictEqual(events, ['a']);
    assert.strictEqual(fake.getTimerCount(), 2);

    await fake.advanceTimersToNextTimerAsync(2);
    assert.deepStrictEqual(events, ['a', 'b', 'c']);
    assert.strictEqual(fake.getTimerCount(), 0);

    fake.useRealTimers();
    fake.dispose();
  }

  // 5. runAllTimers and runAllTimersAsync execute all queued and recursively scheduled timers
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    const nestedOrder = [];
    globalThis.setTimeout(() => {
      nestedOrder.push('level-1');
      globalThis.setTimeout(() => {
        nestedOrder.push('level-2');
        globalThis.setTimeout(() => {
          nestedOrder.push('level-3');
        }, 50);
      }, 50);
    }, 50);

    fake.runAllTimers();
    assert.deepStrictEqual(nestedOrder, ['level-1', 'level-2', 'level-3']);
    assert.strictEqual(fake.getTimerCount(), 0);

    const asyncOrder = [];
    globalThis.setTimeout(() => {
      asyncOrder.push('async-1');
      globalThis.setTimeout(() => {
        asyncOrder.push('async-2');
      }, 20);
    }, 20);

    await fake.runAllTimersAsync();
    assert.deepStrictEqual(asyncOrder, ['async-1', 'async-2']);
    assert.strictEqual(fake.getTimerCount(), 0);

    fake.useRealTimers();
    fake.dispose();
  }

  // 6. runOnlyPendingTimers and runOnlyPendingTimersAsync execute currently queued timers without running newly scheduled nested timers
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    const pendingLog = [];
    globalThis.setTimeout(() => {
      pendingLog.push('parent-1');
      globalThis.setTimeout(() => pendingLog.push('child-1'), 100);
    }, 50);
    globalThis.setTimeout(() => {
      pendingLog.push('parent-2');
    }, 80);

    fake.runOnlyPendingTimers();
    assert.deepStrictEqual(pendingLog, ['parent-1', 'parent-2']);
    assert.strictEqual(fake.getTimerCount(), 1);

    await fake.runOnlyPendingTimersAsync();
    assert.deepStrictEqual(pendingLog, ['parent-1', 'parent-2', 'child-1']);
    assert.strictEqual(fake.getTimerCount(), 0);

    fake.useRealTimers();
    fake.dispose();
  }

  // 7. clearAllTimers and getTimerCount track and cancel active scheduled timers
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    globalThis.setTimeout(() => {}, 100);
    globalThis.setTimeout(() => {}, 200);
    globalThis.setInterval(() => {}, 300);

    assert.strictEqual(fake.getTimerCount(), 3);
    fake.clearAllTimers();
    assert.strictEqual(fake.getTimerCount(), 0);

    fake.useRealTimers();
    fake.dispose();
  }

  // 8. setSystemTime, getRealSystemTime, now, and reset manage and simulate system timestamps
  {
    const fake = createModernFakeTimers();
    fake.useFakeTimers();

    const targetDate = new Date('2026-08-28T00:00:00.000Z');
    fake.setSystemTime(targetDate);

    assert.strictEqual(fake.now(), targetDate.getTime());
    assert.strictEqual(globalThis.Date.now(), targetDate.getTime());

    const realTime = fake.getRealSystemTime();
    assert.strictEqual(typeof realTime, 'number');
    assert.ok(realTime > 0);

    fake.reset();
    fake.useRealTimers();
    fake.dispose();
  }

  // 9. LegacyFakeTimers installs timer mocks, manages clock advancement, and executes runWithRealTimers callback
  {
    const { timers, global } = createLegacyFakeTimers();
    timers.useFakeTimers();

    let legacyCalled = false;
    global.setTimeout(() => {
      legacyCalled = true;
    }, 100);

    assert.strictEqual(timers.getTimerCount(), 1);
    timers.advanceTimersByTime(100);
    assert.strictEqual(legacyCalled, true);
    assert.strictEqual(timers.getTimerCount(), 0);

    let realTimerExecuted = false;
    timers.runWithRealTimers(() => {
      realTimerExecuted = true;
    });
    assert.strictEqual(realTimerExecuted, true);

    timers.useRealTimers();
    timers.dispose();
  }

  // 10. withFakeTimers and withFakeTimersAsync helpers safely execute scoped synchronous and asynchronous callbacks
  {
    const originalSetTimeout = globalThis.setTimeout;

    const syncResult = withFakeTimers((fake) => {
      assert.notStrictEqual(globalThis.setTimeout, originalSetTimeout);
      let executed = false;
      globalThis.setTimeout(() => {
        executed = true;
      }, 50);
      fake.runAllTimers();
      assert.strictEqual(executed, true);
      return 42;
    });
    assert.strictEqual(syncResult, 42);
    assert.strictEqual(globalThis.setTimeout, originalSetTimeout);

    const asyncResult = await withFakeTimersAsync(async (fake) => {
      assert.notStrictEqual(globalThis.setTimeout, originalSetTimeout);
      let executed = false;
      globalThis.setTimeout(() => {
        executed = true;
      }, 100);
      await fake.runAllTimersAsync();
      assert.strictEqual(executed, true);
      return 84;
    });
    assert.strictEqual(asyncResult, 84);
    assert.strictEqual(globalThis.setTimeout, originalSetTimeout);
  }

  console.log('All @jest/fake-timers contract assertions passed successfully.');
}

runContractTests().catch((err) => {
  console.error('Contract test failure:', err);
  process.exit(1);
});

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