CodeSampleX

Sample

@jest/console 29.7.0: console

Verified sample for npm @jest/console 29.7.0: console. The contract ran on node 22 · linux alpine/x64 · docker and passed: BufferedConsole logs standard…

sha256:f3310b6d85e2ead6783373f3d59019fcb1b18db309232a26a57b5126dbc93c46

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment node 22.23 linux 24 · ubuntu · glibc 2.39 x64 node 22.23 javascript npm 10

Verification-run environments

Environment Contract Stages Run
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…		 2026-08-26

Case

HOW
Goal
verify @jest/console in pkg:npm/%40jest/console@29.7.0
Packages
Symbols
  • @jest/console
Environment
node 22.23.2
Created
2026-08-26T01:11:46Z

Contract

  1. BufferedConsole logs standard output levels (log, info, warn, error, debug) into an in-memory buffer with type, message, and caller origin
  2. BufferedConsole.write appends structured log entries directly to a target buffer array
  3. BufferedConsole manages nested indentation levels for grouped logs with group and groupCollapsed while groupEnd resets indentation
  4. BufferedConsole tracks named timers with time and timeEnd and named counters with count and countReset
  5. BufferedConsole.assert logs an AssertionError entry when evaluated condition is falsy and ignores truthy conditions
  6. getConsoleOutput formats buffered console log entries into indented output strings with colorized log types and stack traces
  7. captureConsoleLogs intercepts global console output during function execution and restores the original global console on completion
  8. CustomConsole writes console entries directly to custom writable stdout and stderr streams
  9. NullConsole requires writable streams in constructor and silences all console output without throwing

Files

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

Download the source artifact (tar.gz)

Source

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 @jest/console in pkg:npm/%40jest/console@29.7.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jest/console@29.7.0
Demonstrate these symbols/APIs:
  - @jest/console
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:sha256:1d0bfb4f15b38df9594cd231dfed06f12ddea3f122cd0d6f3d46065288fce9ab","constraints":{"executionContext":"node"},"contract":["BufferedConsole logs standard output levels (log, info, warn, error, debug) into an in-memory buffer with type, message, and caller origin","BufferedConsole.write appends structured log entries directly to a target buffer array","BufferedConsole manages nested indentation levels for grouped logs with group and groupCollapsed while groupEnd resets indentation","BufferedConsole tracks named timers with time and timeEnd and named counters with count and countReset","BufferedConsole.assert logs an AssertionError entry when evaluated condition is falsy and ignores truthy conditions","getConsoleOutput formats buffered console log entries into indented output strings with colorized log types and stack traces","captureConsoleLogs intercepts global console output during function execution and restores the original global console on completion","CustomConsole writes console entries directly to custom writable stdout and stderr streams","NullConsole requires writable streams in constructor and silences all console output without throwing"],"goal":"verify @jest/console in pkg:npm/%40jest/console@29.7.0","kind":"HOW","packages":["pkg:npm/%40jest/console@29.7.0"],"schemaVersion":1,"symbols":["@jest/console"]},"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/console@29.7.0"],"schemaVersion":1,"subject":"pkg:npm/%40jest/console@29.7.0","symbols":["@jest/console"],"verifierAdapter":"node-typescript@1"}
index.js
'use strict';

const { Writable } = require('stream');
const jestConsole = require('@jest/console');
const {
  BufferedConsole,
  CustomConsole,
  NullConsole,
  getConsoleOutput
} = jestConsole;

/**
 * Creates a BufferedConsole instance with an optional source map hook.
 * @param {Function} [getSourceMaps]
 * @returns {BufferedConsole}
 */
function createBufferedConsole(getSourceMaps = () => null) {
  return new BufferedConsole(getSourceMaps);
}

/**
 * Formats buffered console log entries into a formatted string.
 * @param {Array<object>} buffer
 * @param {object} [options]
 * @returns {string}
 */
function formatConsoleEntries(buffer, options = {}) {
  const rootDir = options.rootDir || process.cwd();
  const config = { rootDir };
  const globalConfig = {
    verbose: Boolean(options.verbose),
    noStackTrace: Boolean(options.noStackTrace)
  };
  return getConsoleOutput(buffer, config, globalConfig);
}

/**
 * Executes a callback with global.console replaced by a BufferedConsole,
 * then returns the execution result, collected buffer, and formatted output.
 * @param {Function} callback
 * @param {object} [formatOptions]
 * @returns {{ result: any, buffer: Array<object>, output: string, console: BufferedConsole }}
 */
function captureConsoleLogs(callback, formatOptions = {}) {
  const bufferedConsole = createBufferedConsole();
  const originalConsole = global.console;
  let result;
  try {
    global.console = bufferedConsole;
    result = callback(bufferedConsole);
  } finally {
    global.console = originalConsole;
  }
  const buffer = bufferedConsole.getBuffer() || [];
  const output = formatConsoleEntries(buffer, formatOptions);
  return {
    result,
    buffer,
    output,
    console: bufferedConsole
  };
}

/**
 * Creates a CustomConsole targeting the provided or dev-null writable streams.
 * @param {NodeJS.WritableStream} stdout
 * @param {NodeJS.WritableStream} stderr
 * @param {Function} [formatBuffer]
 * @returns {CustomConsole}
 */
function createCustomConsole(stdout, stderr, formatBuffer) {
  return new CustomConsole(stdout, stderr, formatBuffer);
}

/**
 * Creates a NullConsole instance configured with dev-null writable streams.
 * @param {NodeJS.WritableStream} [stdout]
 * @param {NodeJS.WritableStream} [stderr]
 * @returns {NullConsole}
 */
function createNullConsole(stdout, stderr) {
  const devNull = () =>
    new Writable({
      write(_chunk, _encoding, callback) {
        callback();
      }
    });
  return new NullConsole(stdout || devNull(), stderr || devNull());
}

module.exports = {
  ...jestConsole,
  createBufferedConsole,
  formatConsoleEntries,
  captureConsoleLogs,
  createCustomConsole,
  createNullConsole
};
package-lock.json
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}
package.json
{
  "name": "sample-jest-console-verify",
  "version": "1.0.0",
  "private": true,
  "description": "verify @jest/console in pkg:npm/%40jest/console@29.7.0",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "@jest/console": "29.7.0"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify @jest/console in pkg:npm/%40jest/console@29.7.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jest/console@29.7.0"
  ],
  "symbols": [
    "@jest/console"
  ],
  "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 { Writable } = require('stream');
const {
  BufferedConsole,
  CustomConsole,
  NullConsole,
  getConsoleOutput,
  createBufferedConsole,
  formatConsoleEntries,
  captureConsoleLogs,
  createCustomConsole,
  createNullConsole
} = require('../index.js');

function testBufferedConsoleLogging() {
  const consoleInstance = createBufferedConsole();
  consoleInstance.log('standard log message');
  consoleInstance.info('informational notice');
  consoleInstance.warn('warning notice');
  consoleInstance.error('error event');
  consoleInstance.debug('debug trace');

  const buffer = consoleInstance.getBuffer();
  assert.ok(Array.isArray(buffer), 'buffer must be an array');
  assert.strictEqual(buffer.length, 5, 'buffer must contain exactly 5 entries');

  assert.strictEqual(buffer[0].type, 'log');
  assert.strictEqual(buffer[0].message, 'standard log message');
  assert.ok(typeof buffer[0].origin === 'string' && buffer[0].origin.length > 0);

  assert.strictEqual(buffer[1].type, 'info');
  assert.strictEqual(buffer[1].message, 'informational notice');

  assert.strictEqual(buffer[2].type, 'warn');
  assert.strictEqual(buffer[2].message, 'warning notice');

  assert.strictEqual(buffer[3].type, 'error');
  assert.strictEqual(buffer[3].message, 'error event');

  assert.strictEqual(buffer[4].type, 'debug');
  assert.strictEqual(buffer[4].message, 'debug trace');
}

function testBufferedConsoleStaticWrite() {
  const targetBuffer = [];
  BufferedConsole.write(targetBuffer, 'warn', 'manually written message', 1);

  assert.strictEqual(targetBuffer.length, 1);
  assert.strictEqual(targetBuffer[0].type, 'warn');
  assert.strictEqual(targetBuffer[0].message, 'manually written message');
  assert.ok(typeof targetBuffer[0].origin === 'string');
}

function testBufferedConsoleGrouping() {
  const consoleInstance = createBufferedConsole();
  consoleInstance.group('Parent Group');
  consoleInstance.log('nested item 1');
  consoleInstance.groupCollapsed('Child Group');
  consoleInstance.log('deeply nested item');
  consoleInstance.groupEnd();
  consoleInstance.log('nested item 2');
  consoleInstance.groupEnd();

  const buffer = consoleInstance.getBuffer();
  assert.strictEqual(buffer.length, 5);

  assert.strictEqual(buffer[0].type, 'group');
  assert.strictEqual(buffer[0].message, '  Parent Group');

  assert.strictEqual(buffer[1].type, 'log');
  assert.strictEqual(buffer[1].message, '  nested item 1');

  assert.strictEqual(buffer[2].type, 'groupCollapsed');
  assert.strictEqual(buffer[2].message, '    Child Group');

  assert.strictEqual(buffer[3].type, 'log');
  assert.strictEqual(buffer[3].message, '    deeply nested item');

  assert.strictEqual(buffer[4].type, 'log');
  assert.strictEqual(buffer[4].message, '  nested item 2');
}

function testBufferedConsoleTimersAndCounters() {
  const consoleInstance = createBufferedConsole();
  consoleInstance.count('testCounter');
  consoleInstance.count('testCounter');
  consoleInstance.countReset('testCounter');
  consoleInstance.count('testCounter');

  consoleInstance.time('operationTimer');
  consoleInstance.timeEnd('operationTimer');

  const buffer = consoleInstance.getBuffer();
  assert.strictEqual(buffer[0].message, 'testCounter: 1');
  assert.strictEqual(buffer[1].message, 'testCounter: 2');
  assert.strictEqual(buffer[2].message, 'testCounter: 1');

  assert.strictEqual(buffer[3].type, 'time');
  assert.match(buffer[3].message, /^operationTimer: \d+(\.\d+)?\s*(ms|s)$/);
}

function testBufferedConsoleAssertions() {
  const consoleInstance = createBufferedConsole();
  consoleInstance.assert(true, 'truthy condition must not log');
  assert.strictEqual(consoleInstance.getBuffer(), undefined);

  consoleInstance.assert(false, 'falsy condition logged');
  const buffer = consoleInstance.getBuffer();
  assert.strictEqual(buffer.length, 1);
  assert.strictEqual(buffer[0].type, 'assert');
  assert.match(buffer[0].message, /AssertionError.*falsy condition logged/);
}

function testGetConsoleOutputFormatting() {
  const consoleInstance = createBufferedConsole();
  consoleInstance.log('output formatting log');
  consoleInstance.warn('output formatting warn');
  consoleInstance.error('output formatting error');

  const buffer = consoleInstance.getBuffer();
  const formattedVerbose = formatConsoleEntries(buffer, {
    verbose: true,
    noStackTrace: false
  });
  assert.match(formattedVerbose, /console\.log/);
  assert.match(formattedVerbose, /output formatting log/);
  assert.match(formattedVerbose, /console\.warn/);
  assert.match(formattedVerbose, /output formatting warn/);
  assert.match(formattedVerbose, /console\.error/);
  assert.match(formattedVerbose, /output formatting error/);

  const formattedNoStack = formatConsoleEntries(buffer, {
    verbose: false,
    noStackTrace: true
  });
  assert.match(formattedNoStack, /output formatting log/);
}

function testCaptureConsoleLogs() {
  const result = captureConsoleLogs(() => {
    console.log('intercepted message');
    console.warn('intercepted warning');
    return 'success-value';
  });

  assert.strictEqual(result.result, 'success-value');
  assert.strictEqual(result.buffer.length, 2);
  assert.strictEqual(result.buffer[0].message, 'intercepted message');
  assert.strictEqual(result.buffer[1].message, 'intercepted warning');
  assert.match(result.output, /intercepted message/);
}

function testCustomConsoleStreaming() {
  const stdoutChunks = [];
  const stderrChunks = [];

  const stdoutStream = new Writable({
    write(chunk, encoding, callback) {
      stdoutChunks.push(chunk.toString());
      callback();
    }
  });

  const stderrStream = new Writable({
    write(chunk, encoding, callback) {
      stderrChunks.push(chunk.toString());
      callback();
    }
  });

  const customConsole = createCustomConsole(stdoutStream, stderrStream);
  customConsole.log('stdout message');
  customConsole.error('stderr message');

  assert.strictEqual(stdoutChunks.join(''), 'stdout message\n');
  assert.strictEqual(stderrChunks.join(''), 'stderr message\n');
}

function testNullConsole() {
  assert.throws(
    () => {
      new NullConsole();
    },
    (err) => {
      assert.strictEqual(err.code, 'ERR_CONSOLE_WRITABLE_STREAM');
      return true;
    }
  );

  const nullConsole = createNullConsole();
  nullConsole.log('silenced log');
  nullConsole.info('silenced info');
  nullConsole.warn('silenced warn');
  nullConsole.error('silenced error');
  nullConsole.debug('silenced debug');
}

function runAll() {
  testBufferedConsoleLogging();
  testBufferedConsoleStaticWrite();
  testBufferedConsoleGrouping();
  testBufferedConsoleTimersAndCounters();
  testBufferedConsoleAssertions();
  testGetConsoleOutputFormatting();
  testCaptureConsoleLogs();
  testCustomConsoleStreaming();
  testNullConsole();

  console.log('Contract tests passed successfully.');
}

runAll();

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