bare-stream 2.13.3: duplexPair

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 bare-stream.duplexPair in pkg:npm/bare-stream@2.13.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/bare-stream@2.13.3
Demonstrate these symbols/APIs:
  - bare-stream.duplexPair

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.

# bare-stream duplexPair sample

Demonstrates the usage of `bare-stream.duplexPair` from `bare-stream@2.13.3`.

## Usage

```javascript
import { duplexPair } from 'bare-stream';

const [sideA, sideB] = duplexPair();

sideB.on('data', (chunk) => {
  console.log('Received on sideB:', chunk.toString());
});

sideA.write('Hello via duplexPair');
sideA.end();
```

{"case":{"caseId":"case:sha256:63e22e9a43359530a9965077a3ed8d1e6f30830c8afca5681529cee18a3941e5","contract":["duplexPair returns an array of two Duplex streams","data written to sideA is received on sideB","data written to sideB is received on sideA","ending sideA closes sideB with end event","ending sideB closes sideA with end event"],"goal":"verify bare-stream.duplexPair in pkg:npm/bare-stream@2.13.3","kind":"HOW","packages":["pkg:npm/bare-stream@2.13.3"],"schemaVersion":1,"symbols":["bare-stream.duplexPair"]},"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/bare-stream@2.13.3"],"schemaVersion":1,"subject":"pkg:npm/bare-stream@2.13.3","symbols":["bare-stream.duplexPair"],"verifierAdapter":"node-typescript@1"}

import { duplexPair } from 'bare-stream';

/**
 * Creates a pair of connected duplex streams for in-memory bidirectional communication.
 * Data written to sideA is received on sideB, and data written to sideB is received on sideA.
 *
 * @param {object} [opts] Options passed to the Duplex streams
 * @returns {[import('bare-stream').Duplex, import('bare-stream').Duplex]} [sideA, sideB]
 */
export function createDuplexPair(opts) {
  return duplexPair(opts);
}

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{
  "name": "sample-bare-stream-duplex-pair",
  "version": "1.0.0",
  "type": "module",
  "dependencies": {
    "bare-stream": "2.13.3"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify bare-stream.duplexPair in pkg:npm/bare-stream@2.13.3",
  "kind": "HOW",
  "packages": [
    "pkg:npm/bare-stream@2.13.3"
  ],
  "symbols": [
    "bare-stream.duplexPair"
  ]
}

import assert from 'node:assert/strict';
import { duplexPair, Duplex } from 'bare-stream';

async function testDuplexPairCreation() {
  const pair = duplexPair();
  assert(Array.isArray(pair), 'duplexPair must return an array');
  assert.equal(pair.length, 2, 'duplexPair must return exactly 2 items');

  const [sideA, sideB] = pair;
  assert(sideA instanceof Duplex, 'sideA must be an instance of Duplex');
  assert(sideB instanceof Duplex, 'sideB must be an instance of Duplex');
  assert.equal(typeof sideA.write, 'function', 'sideA must have write function');
  assert.equal(typeof sideB.write, 'function', 'sideB must have write function');
  assert.equal(typeof sideA.read, 'function', 'sideA must have read function');
  assert.equal(typeof sideB.read, 'function', 'sideB must have read function');
}

async function testBidirectionalCommunication() {
  const [sideA, sideB] = duplexPair();

  const sideBReceived = [];
  const sideAReceived = [];

  sideB.on('data', (chunk) => {
    sideBReceived.push(Buffer.isBuffer(chunk) ? chunk.toString() : String(chunk));
  });

  sideA.on('data', (chunk) => {
    sideAReceived.push(Buffer.isBuffer(chunk) ? chunk.toString() : String(chunk));
  });

  const sideBEnded = new Promise((resolve) => sideB.on('end', resolve));
  const sideAEnded = new Promise((resolve) => sideA.on('end', resolve));

  sideA.write('message from A to B');
  sideA.end();

  sideB.write('message from B to A');
  sideB.end();

  await Promise.all([sideAEnded, sideBEnded]);

  assert.deepEqual(sideBReceived, ['message from A to B'], 'sideB should receive payload written to sideA');
  assert.deepEqual(sideAReceived, ['message from B to A'], 'sideA should receive payload written to sideB');
}

async function testMultipleChunksAndOrdering() {
  const [sideA, sideB] = duplexPair();

  const chunksReceivedByB = [];
  sideB.on('data', (chunk) => {
    chunksReceivedByB.push(chunk.toString());
  });

  const bEnd = new Promise((resolve) => sideB.on('end', resolve));

  sideA.write('chunk-1\n');
  sideA.write('chunk-2\n');
  sideA.write('chunk-3\n');
  sideA.end();

  await bEnd;

  assert.equal(chunksReceivedByB.join(''), 'chunk-1\nchunk-2\nchunk-3\n');
}

async function run() {
  await testDuplexPairCreation();
  await testBidirectionalCommunication();
  await testMultipleChunksAndOrdering();
  console.log('All bare-stream duplexPair contract tests passed.');
}

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