end-of-stream 1.4.5

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/end-of-stream@1.4.5
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/end-of-stream@1.4.5

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:sha256:237d34cbfe88de3c55e2989d1f89bc3f3e46ff3d30060bf01e8a2af62ab368e2","contract":["eos invokes the completion callback with no arguments when a Readable stream finishes successfully","eos invokes the completion callback with no arguments when a Writable stream finishes successfully","eos invokes the callback with the emitted error when an error event is fired on the stream","eos invokes the callback with Error('premature close') when a stream is destroyed before completion","eos returns a cleanup function that cancels event listening and prevents callback invocation","eos respects readable and writable options for selective completion tracking on duplex streams"],"goal":"verify pkg:npm/end-of-stream@1.4.5","kind":"HOW","packages":["pkg:npm/end-of-stream@1.4.5"],"schemaVersion":1},"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/end-of-stream@1.4.5"],"schemaVersion":1,"subject":"pkg:npm/end-of-stream@1.4.5","verifierAdapter":"node-typescript@1"}

{
  "name": "sample-end-of-stream",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-end-of-stream",
      "version": "1.0.0",
      "dependencies": {
        "end-of-stream": "1.4.5"
      }
    },
    "node_modules/end-of-stream": {
      "version": "1.4.5",
      "resolved": "https://registry.npmjs.org/end-of-stream/-/end-of-stream-1.4.5.tgz",
      "integrity": "sha512-ooEGc6HP26xXq/N+GCGOT0JKCLDGrq2bQUZrQ7gyrJiZANJ/8YDTxTpQBXGMn+WbIQXNVpyWymm7KYVICQnyOg==",
      "license": "MIT",
      "dependencies": {
        "once": "^1.4.0"
      }
    },
    "node_modules/once": {
      "version": "1.4.0",
      "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
      "integrity": "sha512-lNaJgI+2Q5URQBkccEKHTQOPaXdUxnZZElQTZY0MFUAuaEqe1E+Nyvgdz/aIyNi6Z9MzO5dv1H8n58/GELp3+w==",
      "license": "ISC",
      "dependencies": {
        "wrappy": "1"
      }
    },
    "node_modules/wrappy": {
      "version": "1.0.2",
      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
      "license": "ISC"
    }
  }
}

{
  "name": "sample-end-of-stream",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "end-of-stream": "1.4.5"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/end-of-stream@1.4.5",
  "kind": "HOW",
  "packages": [
    "pkg:npm/end-of-stream@1.4.5"
  ]
}

import assert from 'node:assert/strict';
import { Readable, Writable, PassThrough } from 'node:stream';
import eos from 'end-of-stream';

// 1. eos invokes callback with no arguments when a Readable stream finishes successfully
await new Promise((resolve, reject) => {
	const stream = new Readable({
		read() {
			this.push('chunk');
			this.push(null);
		},
	});

	eos(stream, (err) => {
		try {
			assert.equal(err, undefined);
			resolve();
		} catch (e) {
			reject(e);
		}
	});

	stream.resume(); // consume the stream to reach 'end'
});

// 2. eos invokes callback with no arguments when a Writable stream finishes successfully
await new Promise((resolve, reject) => {
	const stream = new Writable({
		write(chunk, encoding, callback) {
			callback();
		},
	});

	eos(stream, (err) => {
		try {
			assert.equal(err, undefined);
			resolve();
		} catch (e) {
			reject(e);
		}
	});

	stream.write('data');
	stream.end();
});

// 3. eos invokes callback with the error when an 'error' event is emitted on the stream
await new Promise((resolve, reject) => {
	const stream = new PassThrough();
	const testError = new Error('stream failure');

	eos(stream, (err) => {
		try {
			assert.equal(err, testError);
			resolve();
		} catch (e) {
			reject(e);
		}
	});

	stream.emit('error', testError);
});

// 4. eos invokes callback with Error('premature close') when stream is destroyed before completion
await new Promise((resolve, reject) => {
	const stream = new Readable({
		read() {
			// never pushes null
		},
	});

	eos(stream, (err) => {
		try {
			assert.ok(err instanceof Error);
			assert.equal(err.message, 'premature close');
			resolve();
		} catch (e) {
			reject(e);
		}
	});

	stream.destroy();
});

// 5. eos returns a cleanup function that cancels listening and prevents callback execution
await new Promise((resolve, reject) => {
	const stream = new PassThrough();
	let called = false;

	const cancel = eos(stream, () => {
		called = true;
	});

	cancel();
	stream.end();

	setTimeout(() => {
		try {
			assert.equal(called, false);
			resolve();
		} catch (e) {
			reject(e);
		}
	}, 50);
});

// 6. eos respects options: readable/writable selective completion tracking on duplex stream
await new Promise((resolve, reject) => {
	const stream = new PassThrough();

	// Only track writable side
	eos(stream, { readable: false }, (err) => {
		try {
			assert.equal(err, undefined);
			resolve();
		} catch (e) {
			reject(e);
		}
	});

	// Ending writable side triggers callback even though readable side is not closed yet
	stream.end();
});