CodeSampleX

Sample

@jest/console 30.4.1: BufferedConsole

Verified sample for npm @jest/console 30.4.1: BufferedConsole. The contract ran on node 22 · linux debian/x64 · docker and passed.

sha256:a7a38cb22a00ccf1e68aaa911b869dcb54a910e54d875cf3733627f01c5d63b2

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 debian/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1node:22@sha256:8a34c4ab3ea2…		 2026-09-05

Case

HOW
Goal
verify @jest/console.BufferedConsole in pkg:npm/%40jest/console@30.4.1
Packages
Symbols
  • @jest/console.BufferedConsole
Environment
node 22.23.2
Created
2026-09-05T23:54:03Z

Contract

  1. BufferedConsole instances buffer log, info, warn, error, and debug messages with type, message, and caller origin stack trace
  2. BufferedConsole.write appends structured log entries with specified log type directly to a target buffer array
  3. BufferedConsole manages indentation levels for grouped logs with group and groupCollapsed while groupEnd resets indentation
  4. BufferedConsole tracks execution duration with time and timeEnd, and invocation counts with count and countReset
  5. BufferedConsole.assert logs an AssertionError entry when condition is falsy and ignores truthy conditions
  6. BufferedConsole.dir formats JavaScript objects into inspectable string entries in the buffer
  7. captureConsoleLogs intercepts standard console output during function execution and restores the original global console

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.BufferedConsole in pkg:npm/%40jest/console@30.4.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40jest/console@30.4.1
Demonstrate these symbols/APIs:
  - @jest/console.BufferedConsole

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:sha256:4f9cd9196c9c1bfc54423b6cf79087327d91c22c94e93954d2b8be90e65abbda","contract":["BufferedConsole instances buffer log, info, warn, error, and debug messages with type, message, and caller origin stack trace","BufferedConsole.write appends structured log entries with specified log type directly to a target buffer array","BufferedConsole manages indentation levels for grouped logs with group and groupCollapsed while groupEnd resets indentation","BufferedConsole tracks execution duration with time and timeEnd, and invocation counts with count and countReset","BufferedConsole.assert logs an AssertionError entry when condition is falsy and ignores truthy conditions","BufferedConsole.dir formats JavaScript objects into inspectable string entries in the buffer","captureConsoleLogs intercepts standard console output during function execution and restores the original global console"],"goal":"verify @jest/console.BufferedConsole in pkg:npm/%40jest/console@30.4.1","kind":"HOW","packages":["pkg:npm/%40jest/console@30.4.1"],"schemaVersion":1,"symbols":["@jest/console.BufferedConsole"]},"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@30.4.1"],"schemaVersion":1,"subject":"pkg:npm/%40jest/console@30.4.1","symbols":["@jest/console.BufferedConsole"],"verifierAdapter":"node-typescript@1"}
index.js
'use strict';

const { BufferedConsole } = require('@jest/console');

/**
 * Creates an instance of BufferedConsole.
 * @returns {BufferedConsole} A new BufferedConsole instance.
 */
function createBufferedConsole() {
  return new BufferedConsole();
}

/**
 * Appends a log entry directly to a buffer array using BufferedConsole.write.
 * @param {Array<object>} buffer - Destination buffer array.
 * @param {string} type - Log type (e.g. 'log', 'warn', 'error').
 * @param {string} message - The message text.
 * @param {number} [level=0] - Indentation level.
 * @returns {Array<object>} The modified buffer.
 */
function writeToBuffer(buffer, type, message, level = 0) {
  BufferedConsole.write(buffer, type, message, level);
  return buffer;
}

/**
 * Executes a function while intercepting global console calls into a BufferedConsole.
 * Restores global console upon completion or error.
 * @param {Function} fn - Synchronous function to execute with captured console.
 * @returns {{ result: any, buffer: Array<object>, console: BufferedConsole }} Execution result and captured buffer.
 */
function captureConsoleLogs(fn) {
  const bufferedConsole = createBufferedConsole();
  const originalConsole = global.console;
  let result;
  try {
    global.console = bufferedConsole;
    result = fn(bufferedConsole);
  } finally {
    global.console = originalConsole;
  }
  const buffer = bufferedConsole.getBuffer() || [];
  return {
    result,
    buffer,
    console: bufferedConsole
  };
}

module.exports = {
  BufferedConsole,
  createBufferedConsole,
  writeToBuffer,
  captureConsoleLogs
};
package-lock.json
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package.json
{
  "name": "sample-jest-console-buffered",
  "version": "1.0.0",
  "private": true,
  "description": "verify @jest/console.BufferedConsole in pkg:npm/%40jest/console@30.4.1",
  "main": "index.js",
  "scripts": {
    "test": "node test/contract.js"
  },
  "dependencies": {
    "@jest/console": "30.4.1"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify @jest/console.BufferedConsole in pkg:npm/%40jest/console@30.4.1",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40jest/console@30.4.1"
  ],
  "symbols": [
    "@jest/console.BufferedConsole"
  ]
}
test/contract.js
'use strict';

const assert = require('assert');
const {
  BufferedConsole,
  createBufferedConsole,
  writeToBuffer,
  captureConsoleLogs
} = require('../index.js');

function testBufferedConsoleBasicLogging() {
  const c = createBufferedConsole();
  c.log('sample log %s', 'message');
  c.info('sample info message');
  c.warn('sample warn message');
  c.error('sample error message');
  c.debug('sample debug message');

  const buffer = c.getBuffer();
  assert.ok(Array.isArray(buffer), 'buffer should be an array');
  assert.strictEqual(buffer.length, 5, 'buffer should have 5 items');

  assert.strictEqual(buffer[0].type, 'log');
  assert.strictEqual(buffer[0].message, 'sample 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, 'sample info message');

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

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

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

function testBufferedConsoleStaticWrite() {
  const targetBuffer = [];
  writeToBuffer(targetBuffer, 'warn', 'direct buffer append message', 1);

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

function testBufferedConsoleGrouping() {
  const c = createBufferedConsole();
  c.group('Suite 1');
  c.log('test step 1');
  c.groupCollapsed('Nested Step');
  c.log('inner detail');
  c.groupEnd();
  c.log('test step 2');
  c.groupEnd();

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

  assert.strictEqual(buffer[0].type, 'group');
  assert.strictEqual(buffer[0].message, '  Suite 1');

  assert.strictEqual(buffer[1].type, 'log');
  assert.strictEqual(buffer[1].message, '  test step 1');

  assert.strictEqual(buffer[2].type, 'groupCollapsed');
  assert.strictEqual(buffer[2].message, '    Nested Step');

  assert.strictEqual(buffer[3].type, 'log');
  assert.strictEqual(buffer[3].message, '    inner detail');

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

function testBufferedConsoleTimingAndCounting() {
  const c = createBufferedConsole();
  c.count('invocations');
  c.count('invocations');
  c.countReset('invocations');
  c.count('invocations');

  c.time('benchmark');
  c.timeEnd('benchmark');

  const buffer = c.getBuffer();
  assert.strictEqual(buffer.length, 4);

  assert.strictEqual(buffer[0].type, 'count');
  assert.strictEqual(buffer[0].message, 'invocations: 1');

  assert.strictEqual(buffer[1].type, 'count');
  assert.strictEqual(buffer[1].message, 'invocations: 2');

  assert.strictEqual(buffer[2].type, 'count');
  assert.strictEqual(buffer[2].message, 'invocations: 1');

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

function testBufferedConsoleAssertion() {
  const c = createBufferedConsole();
  c.assert(true, 'truthy condition must not produce buffer entry');
  assert.strictEqual(c.getBuffer(), undefined);

  c.assert(false, 'condition failed as expected');
  const buffer = c.getBuffer();
  assert.strictEqual(buffer.length, 1);
  assert.strictEqual(buffer[0].type, 'assert');
  assert.match(buffer[0].message, /AssertionError.*condition failed as expected/);
}

function testBufferedConsoleDir() {
  const c = createBufferedConsole();
  c.dir({ key: 'value', number: 123 });

  const buffer = c.getBuffer();
  assert.strictEqual(buffer.length, 1);
  assert.strictEqual(buffer[0].type, 'dir');
  assert.match(buffer[0].message, /key:\s*'value'/);
}

function testCaptureConsoleLogs() {
  const { result, buffer } = captureConsoleLogs(() => {
    console.log('intercepted standard log');
    console.error('intercepted standard error');
    return 42;
  });

  assert.strictEqual(result, 42);
  assert.strictEqual(buffer.length, 2);
  assert.strictEqual(buffer[0].type, 'log');
  assert.strictEqual(buffer[0].message, 'intercepted standard log');
  assert.strictEqual(buffer[1].type, 'error');
  assert.strictEqual(buffer[1].message, 'intercepted standard error');
}

function main() {
  testBufferedConsoleBasicLogging();
  testBufferedConsoleStaticWrite();
  testBufferedConsoleGrouping();
  testBufferedConsoleTimingAndCounting();
  testBufferedConsoleAssertion();
  testBufferedConsoleDir();
  testCaptureConsoleLogs();
  console.log('All BufferedConsole contract tests passed successfully.');
}

main();

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