split2 4.2.0

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/split2@4.2.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/split2@4.2.0
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - 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.

{"case":{"caseId":"case:sha256:03e961292da654fb3558941038fb3da18e2c5a01b3eca78e7198c4ae5c8160e7","constraints":{"executionContext":"node"},"contract":["split2 transforms streams into individual lines by newline delimiter","split2 supports custom string and regex matchers for stream splitting","split2 supports custom mapper functions to transform parsed tokens"],"goal":"verify pkg:npm/split2@4.2.0","kind":"HOW","packages":["pkg:npm/split2@4.2.0"],"schemaVersion":1},"contractCommand":["node","test/contract.cjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/split2@4.2.0"],"schemaVersion":1,"subject":"pkg:npm/split2@4.2.0","verifierAdapter":"node-typescript@1"}

{
  "name": "split2-sample",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "split2-sample",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "split2": "4.2.0"
      }
    },
    "node_modules/split2": {
      "version": "4.2.0",
      "resolved": "https://registry.npmjs.org/split2/-/split2-4.2.0.tgz",
      "integrity": "sha512-UcjcJOWknrNkF6PLX83qcHM6KHgVKNkV62Y8a5uYDVv9ydGQVwAHMKqHdJje1VTWpljG0WYpCDhrCdAOYH4TWg==",
      "license": "ISC",
      "engines": {
        "node": ">= 10.x"
      }
    }
  }
}

{
  "name": "split2-sample",
  "version": "1.0.0",
  "description": "Verification sample for split2",
  "license": "MIT-0",
  "dependencies": {
    "split2": "4.2.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/split2@4.2.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/split2@4.2.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "runtime": "node@22.23.2"
  }
}

const { Readable } = require('stream');
const assert = require('assert');
const split2 = require('split2');

async function testNewlineSplitting() {
  const input = ['line1\nline2\r\nlin', 'e3\nline4\n'];
  const stream = Readable.from(input).pipe(split2());
  const lines = [];
  for await (const line of stream) {
    lines.push(line);
  }
  assert.deepStrictEqual(lines, ['line1', 'line2', 'line3', 'line4']);
}

async function testCustomMatcher() {
  const input = ['alpha:beta:gamma:delta'];
  const stream = Readable.from(input).pipe(split2(':'));
  const tokens = [];
  for await (const token of stream) {
    tokens.push(token);
  }
  assert.deepStrictEqual(tokens, ['alpha', 'beta', 'gamma', 'delta']);
}

async function testCustomRegexMatcher() {
  const input = ['item1,item2;item3,item4'];
  const stream = Readable.from(input).pipe(split2(/[,;]/));
  const items = [];
  for await (const item of stream) {
    items.push(item);
  }
  assert.deepStrictEqual(items, ['item1', 'item2', 'item3', 'item4']);
}

async function testCustomMapper() {
  const input = ['{"num":1}\n{"num":2}\n'];
  const stream = Readable.from(input).pipe(split2(JSON.parse));
  const parsed = [];
  for await (const obj of stream) {
    parsed.push(obj);
  }
  assert.deepStrictEqual(parsed, [{ num: 1 }, { num: 2 }]);
}

async function run() {
  await testNewlineSplitting();
  await testCustomMatcher();
  await testCustomRegexMatcher();
  await testCustomMapper();
}

run().catch((err) => {
  console.error(err);
  process.exit(1);
});